Tanks

From LoveToKnow 1911

"TANKS. - The name " Tank," applied during the World War to a bullet-proof, armed, track-driven, climbing, automobile, machine-gun destroyer, was first given to an engine of war in Dec. 1915, as a blind to conceal the true nature of the experimental fighting machine then being secretly constructed in England. After the first appearance of the machine in the field in Sept. 1916, the word was universally adopted. It is here used to describe all armed and armoured automobiles of a fighting type propelled on the caterpillar system. To the British is due the credit of first conceiving and introducing this weapon, which was destined to exert a decisive influence on the course of the war on land.

The conditions responsible for the birth of the tank were not in principle new. They were the same as have always existed in war, but intensified by the application of modern methods to the situation unexpectedly created by the course of the land campaign on the western front. Neither the strategic development nor the outcome of its full tactical exploitation had been foreseen. It was owing to this that so vital a factor as the tank proved to be should have had to be improvised during the course of hostilities as the solution of an age-old problem. The problem was that of giving effective assistance, in the shape of direct protection, to infantry advancing under fire.

Apart from cooperation elsewhere, assistance can be given in two ways. It can be effected either by artillery, which with its power of long range action can support advancing infantrymen whilst in motion, and therefore unable to make full use of their rifles, by shooting over their heads, or more directly by the provision of some form of physical protection against blows or missiles. The attempt to provide protection whilst retaining the power of movement both for hand-to-hand fighting and also against missiles, as opposed to that afforded by fortification to troops when stationary, has recurred throughout the history of warfare. The best known examples of it are the shield and body armour carried or worn by the man. Though the need for these did not then cease, their practicability was terminated by the introduction of firearms, since no weight of material that the human being or the horse could carry was of avail against missiles propelled by the force of powder. There was also the idea of giving wheel-borne collective protection to several men at a time, and devices for doing this have been numerous, and have varied according to the progress of mechanical knowledge and the resources available at the moment.

The Assyrians made use of war chariots, or mobile fortresses, which were adopted from them by the Egyptians and Israelites.' Chariots were also employed by the Chinese in 1200 B.C. Then, for siege warfare, there were the Roman Testudo, or " Tortoise," and the medi ae val Beaufroi, or "Belfry," which was usually assisted by the " Cat " or " Sow," an engine of a more mobile type. About 1400 A.D. Conrad Kyeser wrote on this subject, and some 20 years later Fontana and Archinger designed cars, the latter a large machine to carry 100 men. In the middle of the 15th century appeared the " Scottish War Carts," known also as " Tudor War Carts." In 1472 one Valturio designed a machine to be propelled by wind sails. In 1482 Leonardo da Vinci wrote to Ludivico Sforza describing a machine which, except in motive power, was in essentials the counterpart of the tank. A battle car was designed for the Emperor Maximilian I., and in 1558 Holzschuher described one for use with infantry and cavalry. Eleven years later two land battleships are stated to have been built by Simon Stevin for the Prince of Orange. Except those propelled by the wind, all the above were moved by the muscular power of men or horses. In 1634 David Ramsey took out an English patent for a self-moving car, and Caspar Schott designed one for use against the Turks. In 1769 Cugnot, a Frenchman, actually constructed a steam-driven road car which could be used in war; and later Napoleon wrote a paper on the subject of the automobile in war. In 1855 James Cowan, in England took out provisional protection for a " locomotive battery fitted with scythes to mow down infantry," and endeavoured to persuade Lord Palmerston to take up this adaptation of the chariot. Capt. Nadar put forward a similar suggestion in 1870; and in 1900 John Fowler, of Leeds, produced armoured steam traction engines for S. Africa.

The introduction of rifled breech-loading firearms did not force into use any system of man-borne or horse-borne protection, notwithstanding that the range, volume and accuracy of all kinds of fire was immensely increased and its effect rendered correspondingly more deadly. For, it was less possible than it had been to produce shields or body armour which were capable of resisting the greater penetration of the rifle bullet and yet light enough to be carried; whilst no practical method of mechanical propulsion across country of the heavy weights involved in collective protection had been discovered. And yet, as time passed, the need for some more intimate form of help for the infantry soldier than that afforded by artillery grew more insistent. It was accentuated by the invention of the machine-gun and of the magazine and the automatic rifle, and by every successive improvement in small arms or artillery. In point of fact, however, the mechanical difficulties had been overcome some years before 1914. The " caterpillar," or " track," or " endless band " system of propulsion, by which weight is distributed by the increase of the surface bearing on the earth, instead of being concentrated, as with a wheel, and a better tractive effect obtained, which had been known, and in the United States largely employed, for some years, had furnished the key to cross-country mobility; and the perfecting of the internal combustion engine had subsequently given to the world compact power with light weight.

The principle of the " footed wheel," " caterpillar," or " track " system of propulsion appears to have originated in the patent of Richard Lovell Edgeworth in 1770 for a device whereby a portable railway could be attached to a wheeled carriage. 2 This employed the basic principle of all subsequent track-driven machines. Then followed patents for tracks of different natures, by Thomas German in 1801, William Palmer in 1812, John Richard Barry in 1821. In 1846 there was the Boydell engine, with footed wheels, improved upon by Andrew Dunlop in 1861; whilst in 1882 Guillaume Fender and John Newburn designed modifications of tracks. In the following year the actual use of tank-like engines for war was predicted by M. Albert Robeida in La Caricature.' In 1886 there came the Applegarth tractor, and the Batter tractor was patented in the United States two years later. The latter anticipated the tank in many, details. All the above machines were steam propelled. In America steam locomotives with caterpillar tracks, some furnished with sleds ' The greater part of this historical summary is taken from Tanks in the Great War by Brvt.-Col. J. F. C. Fuller, and The Forerunner of the Tank by H. M. Manchester, The American Mechanist, Vol. xlix. No. 15.

2 The Engineer, Aug. 10 1917 and following issues.

3 Strand Magazine, June 1917.

or runners, had for years before the war been applied to haulage in lumber camps. After the appearance of the petrol engine Frank Bramond patented in 1900 a special form of track for pneumatic tired wheels. In 1907 a Rochet-Schneider car fitted with a chain track was tried for military traction purposes, and in 1908 a 70 H.P. Hornsby-Ackroyd chain track tractor took part in a review at Aldershot, and Hornsby also demonstrated a 75 H.P. Mercedes motor car fitted with tracks, a speed of 20 m. an hour being attained on sand. Another British tractor, of the footed wheel type, was the Diplock Pedrail. In America petrol-driven caterpillar tractors had before the war become quite common for agricultural purposes, amongst them being the Bullock, Killen Strait and Holt tractors.

While experiments in petrol-driven caterpillar-track tractors for military use had been carried out by the British authorities before the war, there had been no serious investigation or proposal by any nation to develop the caterpillar principle for fighting as opposed to transport purposes. In 1903 Mr. H. G. Wells had in fiction anticipated the intervention in battle of fighting machines which amounted to large-size tanks. Five years later Capt. T. G. Tulloch had suggested a scheme for a steam-driven pedrail armed and armoured trench-crossing machine, and in 1911 had put forward a proposal to use armed and armoured linked Hornsby-Ackroyd tractors with a crew of a hundred men. And in 1912 Mr. L. E. de Mole, an Australian, actually placed before the War Office a design, followed in ' 9 ' 6 by a model, for a climbing, fighting track-driven machine. This was the real prototype of the tank; and in some particulars, especially its pivoted ends and flexible chain tracks for steering a curved course, it seems to have been superior to the machine actually produced. Unfortunately, whatever may have been official opinions or intentions in regard to this scheme, no action was taken. 4 In Dec. 1915 a caterpillar-track wirecutter, invented by M. J. L. Breton, the French deputy, and called the Tracteur-porte-cisaille, or Tracteur Breton, was tried, and orders were given for a few, which, however, were not constructed. The Boirault cross-country motor, which consisted of an articulated polygon, was also tried, but was found impracticable owing to lack of steering power.

In the years preceding 1914, military opinion generally inclined to the belief that in any future struggle open warfare, or a " war of movement," alone was probable; that in such a campaign mobility was the essential; and that there would not be many occasions when a sheer unassisted frontal attack would have to be pressed to the end against carefully prepared positions held by unshaken defenders. It was appreciated that such operations if attempted would be costly to the infantry, though how costly was not realized. And it was thought that they could usually be avoided by manoeuvre, or, if they had to be carried out, would be assisted by envelopment or flank action which would relieve the task of the infantry by weakening the power or determination of the defence to fight to the end, or by operating at night or by surprise. The other, local, measures for assisting the infantry consisted of the bombardment and supporting fire of the attacking artillery up to the moment of actual assault, and the covering rifle fire from stationary infantry to cover those who could not use their rifles whilst actually moving forward, both of which were intended to keep down the defenders' fire. Great and, as it proved, undue reliance was placed on this concentration of the fire-power of the attack both from artillery and from small arms. It was hoped that by the continual cumulative reinforcement of the firing line until it had arrived at assaulting distance, and possibly dug itself in, a superiority of fire over the defenders would be gained sufficient to permit of the delivery - helped by artillery till the last moment - of the final assault with the bayonet. To enable the firing line to improvise some sort of protection when it could no longer move forward and was " frozen " to the ground, the infantry of all armies were equipped with a portable entrenching tool. The blade of this instrument, it was thought, also, might in some cases serve as a species of shield. Except by the Ger i Mr. de Mole's ideas had no influence on the evolution of the tank, for the originators of the latter were ignorant of his project, which only became generally known after the war, in Oct. 1919, some four years after the Mark I. tank was designed, when the subject came up before the Royal Commission on Awards to Inventors.

mans, wide extension of the attacking infantry was relied on to reduce the casualties. The Germans favoured mass tactics, trusting to break through by weight of numbers in spite of loss.

Up to the outbreak of the war, therefore, partly owing to a wrong estimate of possibilities; to a non-appreciation of the progress of science in its application to warfare; to fallacious reasoning based thereon; to the necessity for economy in military matters; and to the mechanical difficulties which had so long stood in the way and which were still thought to stand in the way, not only had no solution of the problem of providing mobile protection been arrived at, but no serious effort to reach a solution had for a long period been attempted. It followed that when hostilities opened in 1914, save for the development of artillery tactics and materiel, not one of the combatants was really in possession of better means of rendering possible the advance of infantry under fire than those which had been at the disposal of the opposing forces in the Russo-Japanese War of 1904-5. Indeed, in face of the actual growth in strength of the tactical defensive all armies were in this direction relatively weaker than in previous wars of modern days. And the weakness seems to have caused no anxiety. The prevailing complacency, however, was soon to receive a rude awakening.

It might be imagined, since the Germans first assumed the offensive on the western front, that they would have been the first to become aware of this deficiency and to feel the need for mobile protection. This was not so. Though they carried out a succession of attacks during the first month of the war they were not held up, except for a short time before the fortresses Liege, Namur, Maubeuge, and Antwerp, which they reduced by gunfire, and were able until they reached the Marne to continue their onward rush and to maintain their pressure. These attacks, with the exception of the abortive assault on Liege, were not executed against carefully prepared positions such as developed later, and were not usually of a purely frontal nature unassisted by tactical or threatened strategic flank operations or envelopment. Nevertheless, the German losses were extremely heavy, probably more severe than had been expected, but were thought to be the price of the apparent general success of their strategy at the time. They would have been truly justified had the German plan of campaign in fact succeeded. During this period such losses as they suffered were caused mostly by the quick-firing field artillery of the French on the one hand, and on the other by the musketry of the highly trained long-service British infantry hastily entrenched in improvised positions. This, it is stated, was so intense as to lead to the erroneous conclusion that the British Expeditionary Force had been secretly and lavishly equipped with machine-guns. And it was not owing to the strength of the resistance of the British or French field armies on the defensive that the progress of the Germans was finally brought to a standstill at the Marne.

It was only when the roles of the two sides were reversed and the Allies assumed the offensive that the factors first came into play that eventually forced on them a fresh effort to solve the ancient problem. It was then, so far as the British were concerned, that it became apparent that, notwithstanding the weakness shown by permanent forts which had quickly succumbed to the power of specially designed ordnance, not only had the capacity for passive resistance of field defences been much increased, but the active power of the defensive had been very greatly enhanced by the application of modern methods and the scientific employment of modern arms.

More than a hint of this was given first by the nature of the resistance made by the German rear-guards during the battle of the Marne, notably at the crossing of that river at La Ferte-sous-Jouarre on Sept. 9, where the British 4th Div. was held up almost entirely by machine-gun fire in its endeavour to force the passage. It has since become known that the Germans had concentrated at this spot some 42 machine-guns, equivalent to the number of these weapons with 21 British battalions.' Later, during the fighting on the Aisne, greatly as the British were harassed by the German weight of artillery, it was mostly by machine-guns that their efforts to advance were checked, in some instances by the combined action of these "'Die deutsche Kavallerie in Belgien and Frankreich," Von Poseck, p. 102.

guns and obstacles, such as abattis and wire entanglements, which though improvised, were found to be very effective, especially in view of the British weakness in artillery. Even at this early stage so strong were the German defences that the nature of the operations began to approximate to that of siege warfare. Later, at the beginning of Oct., in the more open action when the British endeavoured to outflank the German right to the north of Lille it was the same story. Their progress was in every direction opposed by machineguns, sometimes in the open, sometimes in defended villages or houses, and often protected by improvised entanglements. Almost invariably the presence of German advance troops even in small bodies implied the presence of machine-guns which were handled with the greatest skill. The static warfare which then ensued on the western front during the winter of 1914-5 after the failure of the German offensive and the efforts of both sides to outflank each other on the coast, only accentuated the tendencies already noted. Its effect was to convert the struggle into a species of " field siege " warfare from which all possibility of manoeuvre was excluded and in which all efforts at the offensive had perforce to be attempts to break through, entailing frontal attacks. Nevertheless, though this development had been expected by the Germans no more than by the Allies, and their immense preparations had been based on their original plan of an overwhelming and short offensive campaign on this front, they were in many ways well equipped for it. They were for a long time in possession of an immensely preponderating artillery - an advantage in attack or defence; whilst in defence the nature of the fighting gave full scope to their untiring industry backed up by their genius for field fortification. They also had a great proportion of technical troops and an armament of machineguns far superior to that of the Allies. Though the relative conditions between the sides in these particulars changed, in the struggle which lasted for nearly four years the defensive was for a long time to prove stronger than the offensive, all attempts at which had to be carried out without finesse, by the method of brute force with its prodigal loss of life. It was during this period more especially that the machine-gun was to exert its influence and to reveal to the full its true power in the prepared defensive.

The machine-gun was no new invention, but its possibilities when cleverly used in numbers, though shown to some extent in the Russo-Japanese War of 1904-5, had not been proved. The British and German were equipped with almost identical types of the same gun differing only in detail, both being the outcome of the genius of the late Sir Hiram Maxim. 2 Previous to the Russo-Japanese War the weapon had never been held in great esteem by the British military authorities, except by a few enthusiasts; but the lessons of that campaign had led to an effort to increase the proportion of these guns in the equipment of the army beyond that which existed at the time of the S. African War. But this was not done owing to mistaken ideas of economy. It was also held that superior musketry fire discipline would make up for any deficiency in this respect, and great pains were taken to train the infantry to attain a rate of fire which in fact did exceed that of any other troops. On the other hand the machine-gun had become the weapon par excellence of the Germans. They perhaps of all nations had most correctly gauged its worth, the fact that it combined the maximum of killing power with the minimum of vulnerability, and the economy in a military sense of its adoption on a large scale. And after the Russo-Japanese War they had made a specialty of it. Without ostentatiously increasing the proportion of machineguns with their infantry formations they had armed special units with them and accumulated a large stock in reserve. They had also trained a body of picked officers and men in their technical and tactical use. Their army, therefore, entered the war in this particular better equipped than any other. The first sign of this fact was given by the bold method in which they employed machine-guns in their onrush in the west. The next, as has been said, was the skilful way in which they used them in defence, at first in rear-guard operations, and then in the prepared defensive. In these tactics they excelled, and specialized in combining the intense fire power of the machine-gun with the obstacle - usually barbed wire entanglements - in a way which had never before been done. So far from the weapon being looked upon as a rare article impossible of replacement to be cherished and kept out of danger, it was not considered a disgrace for a gun to be lost once it had earned its value in killing the enemy.. This apparent prodigality was a measure of the 2 The British were equipped with the Vickers, the French with the Hotchkiss, wad the Germans with the Vickers-Maxim.

reserve of weapons available and the chief source of the great increase revealed in the strength of the defensive. The pre-war policy of the Germans was justified in the event. It was the combination of this weapon with barbed wire as initiated by them that suggested the need for the tank. And it was its intensive application and elaboration after the opposing armies had crystallized in two continuous closely opposing lines of carefully entrenched positions extending from the sea to Switzerland, that eventually brought the tank into being.

British Tanks Early in Oct. 1914, it was borne in on the mind of a British officer who had special opportunities for ascertaining what was actually occurring, that the frontal assault of prepared positions, especially when adequate artillery cooperation was not available, had become impossible unless some more effective assistance could be rendered to the infantry than that previously contemplated and accepted as adequate; that this assistance in the absence of gun power and ammunition sufficient to blast a way through the whole enemy system of defences - trenches, obstacles and machine-guns - should consist of some protected powerdriven machine which could force itself through barbed wire, climb across trenches and destroy by gunfire or crush by its weight the machine-guns of the defence. Knowing of the existence and cross-country capabilities of the American Holt caterpillar tractor, it occurred to him that a specially designed machine developed on similar lines would be the solution of the problem. This officer, Lt.-Col. (later Maj.-Gen.) E. D. Swinton, R.E., at that time acting as official military correspondent (" Eyewitness ") with the British Expeditionary Force, was the first officially to put forward a scheme for a caterpillar machine-gun destroyer, in a communication to the Secretary of the Committee of Imperial Defence in London on Oct. 20 1914.1 Though the machine then contemplated and finally evolved was for the purpose of giving infantry protection when advancing, it was expressly designed to do this indirectly, by its own offensive and destructive action. It was definitely intended, and designed, for the express purpose of forcing its way through wire and crossing trenches and hunting for machine-guns in order to destroy them by shell fire or to crush them by passing over them. The only " protection " - using the word in its limited, and more usually accepted sense - afforded by it was that of its bullet-proof sides to its own fighting crew. This point is accentuated because of the misconceptions which have existed as to the role of the tank, chiefly as to its being an armoured vehicle for transporting men, or a mobile shield to give cover to those moving up behind it. It did in fact perform this latter service, but only incidentally, in its quest for machine-guns. Machines for carrying up bodies of infantry and stores were not actually developed until three years later as an extension of the principle. As will be seen, the necessity for finding some mechanical method of carrying troops under cover across country had already occurred independently to a French officer. And in England similar suggestions were put forward, also independently, by Lt. R. F. Macfie, in Aug., and Lt. B. J. F. Bentley in Oct. 1914.

The history of the tank from Oct. 1914, until it took the field 23 months later, and even afterwards, is a record of progress made often in the face of apathy, scepticism and even opposition. This is typical of the history of the evolution of most inventions or new ideas, but is somewhat remarkable in this instance because the subject was one of vital urgency immediately concerning the lives of the British troops in the field. It is also remarkable for another reason. The idea of this land weapon not only received its first help toward realization from the minister responsible for the navy, but its realization was, indeed, only rendered possible by the financial support given by him from naval funds. The gist of the suggestion made to the Secretary of the Committee of Imperial Defence in Oct. 1914 was put forward by him in a memorandum and reached the First Lord of the Admiralty, Mr. Winston Churchill, who was 1 For the origin of the tank see the Minutes of the Proceedings before the Royal Commission on Awards to Inventors, Oct. 1919.

predisposed towards experiments in the direction of some mechanical armoured device for carrying troops across country, to take the place of the armoured motor car which could only operate on roads. A certain number of these cars, belonging to the armoured car section of the Royal Naval Air Service, organized by the Admiralty, had been operating in France and Belgium, and their utility had become seriously curtailed by the destruction of the roads and the state of trench warfare which had arisen. In Jan. 1915, the First Lord, to whom the employment of mobile bullet-proof shields had already been suggested, took up the question of the urgent need for methods of meeting the deadlock reached on land, and his views were officially brought to the notice of the army authorities. He did not, however, only place the matter before the military. He caused researches to be made in the direction of crossing trenches by means of tractors carrying portable bridges, and in Feb. summoned a special Admiralty expert committee under the chairmanship of Mr. (later Sir) E. H. Tennyson d'Eyncourt, the Director of Naval Construction, to explore further the subject of mechanical cross-country transport generally. This committee at once started work and continued its labour for some time, experimenting chiefly in the direction of " landships " with large wheels, coupled steam rollers, pedrail and caterpillar tractors, single and articulated, for which suggestions had been put forward by different individuals. The underlying idea of all these investigations was the production of a machine for the conveyance of troops, not a machine-gun destroyer.

Previous to the receipt of the First Lord's views, the need of a specific machine-gun destroyer had been urged on the War Office directly by Col. Swinton early in Jan. 1915, followed by representations fron Capt. Tulloch. The War Office took the matter up, but did not associate itself with outside technical experts to investigate possibilities, as had been recommended. After the trial and failure in Feb. of a Holt caterpillar tractor to cross obstacles which it was not designed to negotiate, and that of a wheeled tractor with the naval trench bridging device in May, it dropped the whole idea as impracticable. Meanwhile the Admiralty committee had continued its experiments, though without knowledge of the conditions of the military problems it was required to solve. In June, the War Office, then aware of the Admiralty's activities, became desirous of collaborating in them, and a joint naval and military committee was formed. The efforts of the Admiralty thus obtained the first official recognition of the service for whose benefit it was really working. At the end of the month the committee was furnished by the War Office with a detailed specification of the requirements of the destroyer as prepared by Col. Swinton and forwarded by the Commander-in-Chief in France, and the Admiralty designers were for the first time in a position to apply their inventive faculties to fulfilling certain definite conditions. The result of their efforts was the production in Jan. 1916 of an experimental machine paid for entirely from naval funds and produced almost entirely by naval agency, which was the prototype of all British machines. The chief point of its design, and on which it differed from other caterpillar machines, was its rhomboidal shape and allround track, which were the invention of Lt. (later Lt.-Col.) W. G. Wilson, of the Admiralty landships committee, working in conjunction with Mr. (later Sir) W. Tritton. This machine, afterwards known as the Mark I. Tank, successfully underwent its official trials on Feb. 2.2 As has been said, at the beginning of the war the solution of the problem of enabling a frontal attack on trenches to be carried out had been thought to lie very largely in bombardment by artillery. But the futility of the limited bombardment by field guns with shrapnel shell, which was all that was possible for some months even against such comparatively weak defences as the Germans at first held, became apparent. Then, in reply to 2 For purposes of secrecy the name " Tank " had been applied in Dec. 1915 to the experimental machine under construction, then known as a " landship," in a report by a sub-committee of the committee of Imperial Defence. It was suggested by two officers connected with that committee. The experimental machine was afterwards known as Big Willie, and, though a male, as " Mother." the insistent demand from the front the national energies had been turned to the making of guns and ammunition of all types, and prodigious quantities had been produced. But after the battle of Loos it began to be realized that even a great concentration of artillery and the expenditure of an immense amount of ammunition in a prolonged bombardment from guns of all calibres was not necessarily effective against such defences as the Germans had created, and could not insure that the assaulting infantry would not be held up by uncut wire and suffer terrible loss from concealed and protected machine-guns. Some other means of dealing with the numbers of these weapons which would survive a bombardment even of the heaviest nature was necessary. As a result of the performance of the experimental tank in Feb. 1915, G.H.Q. France came to the FIG. i. - Mark I. Tank.

conclusion that such machines might be of some assistance, and made a demand for 40.1 This number was increased by the British War Office to 100, and supply was undertaken by the Tank Supply Committee of the Ministry of Munitions, composed of members representing interests directly concerned, under the chairmanship of Maj. (later Sir) Albert Stern. Orders were placed on Feb. 12, and production was commenced at once with the utmost secrecy, under great difficulties of labour and material owing to the great national effort then in full swing to produce munitions of all sorts.

During this initial period of manufacture various minor improvements of the original design were incorporated. The 1 The first order placed by the French army - headquarters, without awaiting the construction of an experimental machine was for 400 machines, and this was increased to 800.

sample machine, in accordance with the original specification for a machine-gun destroyer, was armed with two 6-pdr. guns and three Hotchkiss machine-guns. It was soon realized that,. though effective for its purpose, this armament was deficient in man-killing fire-power for self-defence in the event of attack by large numbers of men, and it was decided to arm a certain proportion of tanks with four Vickers machine-guns instead of two 6-pounders. They were known as " females," the gunned machines being known as " males." The total number under construction was 150, half males and half females.

The Mark I. Tank (see figs. i and 2). - Details of this machine are given in the table on p. 697, but since all the succeeding machines were a development of it, some further description is given. Its main characteristic was the all-round track, which gave it its climbing power. This was perpetuated in all the British heavy tanks, though in the medium, or " Whippet," tanks evolved later, the same result was obtained by the projection of the tracks which were not under the machine. The essential value of both forms of construction was that whatever the fore and aft angle of the machine with. the horizontal a gripping surface was presented. This was achieved by the high, curved bows, rendered possible by combining the body and the chassis of the machine and using the sides of the body to support the tracks. The length was 32 ft. 6 in., over all, and 21 ft. 5 in. without the tail. The width was 13 ft. 9 in.; the height 8 ft.

inch. Power was given by a six-cylinder sleeve valve Daimler engine of 105 H.P.; transmission consisted of a cone clutch, primary (two speed) gear box (controlled by the driver) differential secondary (two speed) gears, actuated by hand levers, one to each track, and chain drives to the driving sprockets at the rear of each track. There were thus four speeds ahead. This system necessitated a " gearsman " at each side, and was inconvenient and clumsy. The petrol feed was by gravity. There was no silencer. The armour plate varied from 12 mm. thickness in front to 6 mm. at the top and on the belly, the only part proof against the German " K " (armour-piercing) bullet being that 12 mm. thick. The armament of the male tank comprised two 6-pdr. guns, one on each side and four Hotchkiss machine-guns, and that of the female tank two Vickers machine-guns on each side and three Hotchkiss machine-guns. Owing to the pressure of time certain details in the design and equipment of the machine were adopted in order to employ material which was in production and quickly obtainable without waiting for special manufacture. The power unit, including the engine, with gear-box and differential was adopted because it was the standard power unit of an existing tractor and already in production. The 6-pdr. gun was adopted not because it was considered the best for dealing with machine-guns (the 2-pdr. automatic gun was originally specified), but because the Admiralty had a large number of these guns in hand and promised to supply the requisite number to the army. The 6-pdr. proved, however, to be a very good weapon for its purpose. The male tank carried 324 rounds of 6-pdr. common shell for the 6-pdr. gun and 6,272 rounds of S. A. A.; the female carried 31,232 rounds of S.A.A.2 The crew consisted of one officer and seven other ranks. The driver sat with the officer in the conning tower in front. The total weight of the male tank when loaded was 28 tons; of the female 27 tons. The average speed across country was 2 m. per hour, and the radius of action, nominally 23 m., averaged 12 m. over rough ground.

a It was originally proposed to carry a certain proportion of case shot. This was not done, but it was found necessary later to do this.

23' e =---- 26 ' 5 lipgx ox FIG. 2. - Mark I. Tank.

tank could cross trenches up to i i ft. 6 in. in width and could climb a vertical height up to 5 feet. Six of the first establishments of tanks were equipped with a wireless set capable of sending and also to some degree of receiving.' Two features of the Mark I. tank were not perpetuated in later patterns, except in the first gun-carrier machines. One was the tail. This consisted of a pair of wheels carried by a frame pivoted at the stern of the machine which for ordinary steering could be actuated by the driver by means of wire cables. For sharp turns, which were effected by driving on one track alone, they could be raised off the surface of the ground by a hydraulic ram at the back of the tank. The weight of this tail attachment also served to ease the rate of descent of the tank after crossing a summit, and the extra length it gave to the whole machine increased the width of the gap which could be crossed. It was found in actual practice that the complication and liability to damage the tail was not compensated for by its advantages, and its use was abandoned after the first actions. In both the male and female Mark I. machines the 6-pdr. and Vickers machine-guns were mounted in sponsons to give as far as possible arcs of fire up" to direct ahead and astern. In order to reduce the width so that the tanks could be carried by rail these sponsons were removable and could be unshipped for travelling, when they were carried on small wheeled trollies. The inconvenience of this system caused it to be abandoned, and in later patterns of tank the sponsons were so designed that when travelling they could be swung inwards and housed in the width of the tank, or could be unbolted and slid in.

In March 1916, measures were taken to provide the personnel to handle the new weapon, and an establishment was framed for a unit. For secrecy this unit, under the command of Col. Swinton, was raised and formed, as a portion of an existing service, under the name of the " Heavy Section," subsequently changed to " Heavy Branch," of the Machine-Gun Corps. This was to provide the personnel for the 150 tanks then under construction, without any reserve of machines or man-power. At first the organization was for three battalions of 50 tanks each, but this was altered to six companies of 25 tanks each, each company consisting of four sections of six tanks and one spare tank. Each section was formed of three male and three female machines, and was subdivided into three sub-sections of one male and one female tank. A specially constructed and equipped mobile field workshop was allotted to each two companies. To assist in the formation of this unit a nucleus of officers and men were transferred from the existing Motor Machine-Gun Corps; officers also being obtained from the cadet battalions, and from France, and other ranks being enlisted from the motor trade. Technical personnel of all ranks was supplied by the Mechanical Transport Branch of the Royal Army Service Corps.

The first headquarters of the Heavy Branch were at Bisley, where, since there were no machines, the training was of a preliminary nature confined to discipline and gunnery and the use of the Vickers and Hotchkiss machine-guns. Training in gunnery was carried out by means of borrowed guns, and entailed the sending of the men to Salisbury Plain and to the Naval School of Gunnery at Whale Island. So soon as the tanks began to be delivered from the contractors, the training in driving, tactics and shooting from tanks etc., was carried on in a secret area at Elveden in Suffolk, where a facsimile battlefield had been prepared. The whole of this work was carried out under immense difficulties as regards time and the need for secrecy, the main underlying idea of all the preparation being that the role of the unit was to assist and help the infantry. By the beginning of Aug. several machines had been delivered, and a certain amount of training in their use had been carried out.

Meanwhile, the Somme offensive having come to a standstill in spite of the power of the British artillery then available, it was decided to use the tanks, or whatever of them were ready, in the renewal of the attack. Two companies of the heavy branch, 50 tanks with 10 spare machines, were accordingly concentrated in France for this purpose by the end of Aug., and training was continued preparatory to taking part in operations. Friday, Sept. 15, was to mark the appearance of the tank in warfare, when the secret of the new weapon which had been so carefully kept would be revealed and the weapon itself put to the test. The whole production of the unit up to this time was a remarkable feat. Not only had a number of entirely new 1 This scheme was also abandoned and later found necessary..

machines been manufactured sufficient for 60 to take the field within six months of the order for them having been placed at a time of great industrial stress, but the secret of their creation, which was known to thousands, had been so well kept that they did actually come as a surprise to the enemy.

It was to assist in the further advance of the British right flank, which had begun so successfully at the opening of the battle 10 weeks before, between the Somme and the Ancre that the tanks were to be thrown into the fight. The IV. Army was to break through the enemy's front between the Combles ravine and Martinpuich and seize Morval, Les Boeufs, Gueudecourt and Flers. On its left the Reserve V. Army was to attack and gain Martinpuich and Courcelette while the French were to press on its right. The cavalry were to follow up through the gap which it was hoped would be created and seize the high ground about Rocquigny - Villers au Flos - Riencourtlez - Bapaume. Two companies of the tanks were engaged, the bulk with the IV. Army, the rest with the Reserve Army. The general idea of their tactics was that they should start so as to reach their objectives five minutes before the infantry. They were to act in small detachments of two or three machines against the strong points in the enemy's defensive system, lanes being left for their advance in the artillery barrage commencing at zero hour.

The tanks advanced at dawn in a slight mist and came as a complete surprise to the enemy. The operations of those with the XV. Corps of the IV. Army were the most successful; but for various reasons the results of the employment of tanks was somewhat disappointing. Of the 49 machines taking part 32 alone reached their starting points, 9 pushed ahead with the infantry and caused considerable loss to the enemy and 9 others, which did not catch up the infantry, did good work in dispersing of the enemy still holding out at isolated spots; of the balance of 14, 9 broke down and 5 became " ditched." (Ditching was usually caused either by a tank getting into such a position in a deep and wide crater or trench that its engine power was not sufficient to pull it out, though the tracks gripped, or by weight of the machine being taken by its belly on hard ground, in which case the tracks revolved without biting.) One tank gave remarkable help to the infantry held up in front of Flers by wire and machine-gun fire, when by its action it caused the surrender of 300 Germans and enabled the infantry to move on. Another destroyed a field gun. On Sept. 25 and 26, 13 machines acted with the IV. and Reserve Armies. Of these nine were ditched in shell craters, two reached the village of Thiepval and stuck there. But again, as a set-off to mishaps, one single tank on the 26th performed a remarkable feat which demonstrated the potentialities of the machine. Within one hour, and at the expense of five British casualties, it made possible the capture of a strongly held, well wired, trench (the Gird trench) some 1,500 yd. long and strengthened by numerous strong points, which had held up a whole brigade of infantry since the previous evening. The Germans suffered heavy loss, and 8 officers and 362, other ranks, surrendered. On Nov. 13, at the battle of the Ancre after heavy rain, of five tanks that went into action, all became ditched, two machines doing very valuable work before this happened. Next day, in an attack on a field work south of Beaumont Hamel, one machine out of three employed was put out of action by shell fire, and two became ditched. The latter, however, were able to bring so effective a fire on the strong point that it surrendered and 400 prisoners were collected by the tank crews. But, whatever their defects, the tanks had passed with ease through all entanglements and had destroyed many machine-guns, which weapons, indeed, were practically powerless against it.

The employment of the tanks in Sept. 1916 was contrary to the views of those who had originated the Arm, who were responsible for its production and had most studied its action. They held that the utmost value should be obtained from the new weapon and that the secret of its existence should not be given away until a surprise attack could be carried out on a sufficiently extensive scale to give a chance of achieving a decisive success. In this sense the launching of the tanks was a repetition of the error made by the Germans when they released gas on a small section alone on April 22 1915. Whatever may have been the urgency at that time of reviving the momentum of the Somme offensive, which had died away after weeks of great endeavour and immense sacrifice, and of raising the moral of the tired troops, and whatever might have been the success of the new weapon, it is doubtful if the small number actually employed could have given a result to compensate for the premature disclosure of the secret, which in potential value was equal to that of the 42-cm. howitzers and the poison-gas of the enemy. Again, not only was a small number of tanks used, but they were employed in driblets in different directions, instead of together in as great a mass as their available number would allow. As an experiment this trial of the tanks was, no doubt, productive of valuable lessons, but they were obtained at the cost of discounting the future. It was in the face of a considerable amount of scepticism that the machines took their place in the battle-line, and those who did not believe in them, without looking beyond the lack of any startling success achieved on a great scale, were not slow in their condemnation. But one thing the tank had definitely proved: The machine-gun and the barbed wire entanglement no longer ruled the infantry battle. In the tank, still experimental and imperfect as it was, they had found their master. At last attacking infant r y could meet the defence on more than equal terms.

On the part of the tanks themselves there was mechanical failure of machines, which were the first of their kind, tried under more difficult conditions than those which they had been designed to meet. The specification in which they had been constructed had been based on the requirements of the spring of 1915 at a time when the prolonged shelling, such as in 1916 and later rendered whole tracts almost impassable even by infantry, was undreamt of. At the Somme the tanks had to cross a dry " crumped " area, and at the Ancre a combination of " Grumped " area and morass. There were, in addition, breakdowns due to faulty design and to the unexpected wear and tear of certain parts of the machinery, which only experience could have shown should have been of special material and which were, moreover, practically worn out by practice and demonstrations before the action. Failures were also due to the lack of time for the complete training and practice of the crews; to insufficient preparation in the way of reconnaissance and supply services, which for such complicated machines necessitated very complete organization. On the other hand, many of the commanders at whose disposal tanks were placed had no idea of their capabilities, weaknesses or limitations. Nevertheless, the outstanding brilliant exploits of single machines which did not break down, the great saving of life for which the tanks as a whole were responsible, and the demoralizing effect of their appearance on the enemy and the great encouragement afforded to the British infantry, clearly showed that the machines were sound in principle, only needing improvement in detail, and that those handling them required more experience in this new form of warfare.

As a result of its trial it was decided that the new Arm should not only continue, but should be expanded to a force of r,000 tanks. After the fighting on the Ancre the unit did not again go into action till April of the following year, which allowed of a period for expansion, reorganization and training, and the incorporation of improvements to machines.' The expansion of the Heavy Branch of the Machine-Gun Corps was to be on the following lines: there was to be a fighting headquarters in France and an administrative headquarters in England. 2 The six original companies were to be expanded to four battalions in France and the two companies at home to five battalions, or nine battalions in all. The unit therefore reverted to its original battalion organization. It was eventually to comprise three brigades, each of three battalions, each battalion of three companies and a workshop, each company consisting of four fighting sections of five tanks each and a headquarters section of four tanks, or 72 tanks to a battalion. The number of tanks per section was shortly afterwards reduced to four, making 20 per company or 60 per battalion. These brigades were formed at the beginning of 1917, and the organization continued unchanged until June, but though the personnel was being raised and trained as far as possible on this extended scale, the supply of tanks did not keep pace, so much so that on April 1, when it was decided that the tanks should take part in the battle of Arras, only 60 Mark I. and Mark II. machines could be counted on for action.

In Feb. 1916, when the original Mark I. tank was still in its experimental stage, designs had been got out for a Mark II. machine and a Mark III, machine, both of which were slightly improved Mark I. tanks. After the Somme battle certain modifications which were found necessary were incorporated, and in 1 The most important improvement was the improvised " unditching beam " which was introduced to assist a tank to extricate itself when stuck. In the later types a specially designed contrivance was part of the equipment of the machine.

2 Lt.-Col. (afterwards Maj.-Gen.) H. J. Elles, R.E., was appointed colonel commanding the unit in France, Brig.-Gen. F. Gore Anley being appointed administrative commander of the tank training centre in England on Nov. 9. In May 1917 Brig.-Gen. Anley was succeeded by Maj.-Gen. Sir J. E. Capper. The training centre was moved to Bovington in Dorset.

Oct., in order to keep up continuity of supply, orders were given for so machines of each type (making 250 tanks ordered in all) pending the decision on the design for the r,000 asked for by the army, in Sept. The chief improvements consisted of the abandonment of the tail, as already mentioned; the addition of " spuds," or fins, to the track plates, to give a better grip; and the provision of improved rollers. The Mark III. machines were also intended to have thicker armour to resist the " K " bullet. In regard to the r,000 new tanks preliminary orders to collect material were given to the manufacturers in Sept. At the end of the month when it was learnt that these machines could not be ready by March i (partly owing to the manufacture of spare parts necessary for the existing tanks), the demand was cancelled, but was renewed two weeks later. This is men FIG. 3. - Mark IV. Tank.

tioned to show that military opinion as to the advisability of proceeding with the new weapon was not unanimously favourable. The r,000 machines were to be of the type known as the Mark.

IV., which was a much improved Mark I. tank. It was then anticipated that this number could be delivered by the end of June. Owing to various difficulties this estimate was not fulfilled, but sufficient machines reached France in time to equip two battalions for the attack on Messines in May; and it was the standard British tank during 1917 and 1918.

FIG. 4. - Mark IV. Tank.

The Mark IV. tank (see figs. 3 and 4). - The first advance from the original weapon was the same in size and general design, with certain improvements. There was no tail. The track rollers were better. The sponsons could be housed within the tank for rail transport. The Lewis machine-gun was installed instead of the Hotchkiss machine-gun (this was not an improvement and was reversed later). A better radiator was fitted and also a silencer. The width of the driver's cab was increased to allow of wider track shoes. The petrol tanks were placed outside the tank at the stern. A short 6pdr. gun was adopted. Detachable spuds were fitted to the tracks, and unditching gear provided. The entrances and exits were more accessible.

During the Verdun offensive early in 1916 it had occurred to those responsible for the production of the fighting tank that one reason why the Germans had been unable to keep up the initial pressure of their attack was their inability to bring up their artillery and ammunition over the shelled and entrenched area so as to keep pace with their advance; and that if they had been in possession of guns mounted on self-propelled carriages, or carriers on caterpillar tracks, it would have assisted them greatly. A design was therefore prepared in July of a " guncarrying " tank (see fig. 5), to carry a 60-pdr. gun or 6-in. howitzer which could be fired from the tank if necessary or conveyed by the tank and fired from the ground. Of these machines, FIG. 5. - Gun-carrying Tank.

48 were made, delivery in France commencing in July 1917. They appear to have been employed as much for the conveyance of ammunition and stores as for the purpose for which they were designed. In Dec. 1916, also, the design of the " Whippet," the Medium Mark A. tank, (see figs. 6 and 7) was commenced. Of this type 200 machines were produced, delivery in France starting at the end of 1917. It was evolved to be complementary to the heavy tanks and to meet the demand for a speedier, handier machine which could be produced in large numbers. Its main points were its increased speed, nominally 8 m. per hour on the flat, and an average across-country of 5 m. per hour, and its lightness, one-half that of the Mark I. machine. It was also easier to transport by rail. Each track was driven independently by a four-cylinder 45 H.P. Tylor engine. Transmission was by cone clutches to gear boxes of the constant mesh type, giving four speeds forward and one reverse. The design was largely due to Sir W. Tritton. Thus, at the end of 1916, in addition to the first type of heavy tank in the field, measures were in hand to supply a much improved pattern of that machine (Mark IV.) and also a lighter type - the " Whippet." FIG. 6. - Medium Mark A. or " Whippet " Tank.

In the field, though there was still considerable doubt as to the value of tanks, the next six months, from Oct. 1916, were, as had been said, a period of expansion, organization and training, and preparation for the operations of 1917. The training was always handicapped by the paucity of machines; and it was found necessary not only to educate the members of the new arm itself but also other arms and the staff. Headquarters, schools and rest camps and the usual organization of a large unit were established. The next action in which the tanks took part was the battle of Arras on April 9, when an attack was carried out by the I., III. and V. Armies in order to penetrate the German line by a sudden blow and allow of an army corps and two divisions of cavalry to break through. From the point of view of tanks it does not require much comment. Only 60 machines were available, and. they were again not employed in FIG. 7. - Medium Mark A. or " Whippet " Tank.

a mass for a quick penetration but for " mopping up " operations along the whole front.' More complete preparations were made for their cooperation than at the Somme. The battle was prepared by a prolonged bombardment, and was also preceded by heavy rain at the last moment, which combined to produce a sea of mud pitted with craters. The Vimy Ridge was captured by a rush of the Canadians which rendered tanks unnecessary, and on other parts of the front they had varying success, but gave valuable assistance. Against Bullecourt on the 11th, where they attacked without artillery preparation in the snow, the attack was a failure, though two tanks penetrated five miles behind the German front line, when they were captured. Fighting continued till the 2 2nd. The cavalry were prevented from breaking through by the usual obstacles - barbed wire and machine-guns. It was on the first day of the fight that the first German " tank trap " was discovered consisting of a deep covered-in pit. Again the main lesson learned was that tanks should be used in mass and not dispersed. After this battle an expansion of the Heavy Branch, Machine-Gun Corps, from 9 to 18 battalions (nine of heavy tanks and nine of medium machines) was decided on. But at the end of June this expansion was suspended owing to shortage of man-power, as it was apparently not yet realized to what extent the tanks reduced casualties. Before the next action, the battle of Messines, a certain number of the new Mark IV. tanks had been received and several of the old Mark I. and Mark II. machines had been converted into supply tanks for carrying tank stores to the fighting machines, a very great advantage the want of which had previously been much felt. In the attack on the Messines - Wytschaete Ridge, which started on June 7, 76 Mark IV. and 12 supply tanks took part. The operations in this case approximated to the " assault " in the old form of siege warfare and depended mostly on an intense bombardment, lasting from May 28 to June 7, and the explosion of 20 large mines. During 1 " Mopping up " consisted of disposing of small bodies of the enemy, especially such as had escaped the bombardment and allowed the first line of the assault to pass them.

the infantry advance on Wytschaete the creeping barrage proved so effective that tanks were only necessary at different spots to overcome individual machine-guns. They advanced in two lines, the first of 40 machines, going forward at zero (dawn), and the second, of 34 machines, at 3 P.M. to the Oosttaverne line, where their help was very valuable. Apart from the debated point whether the third battle of Ypres should ever have been fought or not, the work of the tanks in it needs still less comment than at Arras or Messines. In spite of remarkable feats accomplished by them, especially the capture of the Cockcroft, a nest of strong points, on Aug. 19 with a loss of 15 infantry, it was, on the whole so far as they were concerned, a failure, and a failure which was inevitable and to be expected under the conditions which existed. They had to act in a lowlying area which had been converted into a potential swamp through the destruction of the drainage system by the artillery of both sides, rendered still worse by the churning up of the surface into a wilderness of craters, which were filled by heavy rain just before the battle. The only means of approach across this morass were the causeways, which were naturally kept continuously under fire by the enemy. Preceded by many days of intense bombardment the attack commenced on July 31, and as it continued the rain made matters worse. That tanks should have been expected to function under such conditions, when, independently of the enemy's action, even the infantry were unable to move forward, is astonishing. It shows that those responsible for the decision to employ them were ignorant either of the situation or the limitations of the machines, or both.

It was not till Nov. 20, when the tanks had been in France over a year, that they were given an opportunity of showing of what they were capable when employed on a large scale, in a manner calculated to exploit their peculiar attributes, and under favourable conditions. As this was a turning-point in the history of the new weapon it is of importance that it be described in detail.

During 1916 and the greater part of 1917 the tanks had been thrown into the fight in dispersed detachments to assist in overcoming certain points of resistance, and somewhat casually as an aid to the attacking infantry. The conditions, also, had usually been such as to render success doubtful, sometimes impossible, and in any case of a minor nature. In several instances they had succeeded in achieving their immediate object and had undoubtedly saved many lives. In others they had failed. As a consequence it was seriously discussed whether tanks should not be abandoned as useless.

But those responsible for the Tank Corps (the name of the unit had been changed to " Tank Corps " at the end of June) had been concerned in thinking out an operation which would not only be strategically valuable, but would enable the corps definitely to prove its worth and establish a confidence in itself, which, never very marked on the part of General Headquarters, had recently been much shaken. Broadly, the scheme consisted in launching without any preliminary bombardment a surprise attack on a large scale with as many tanks as possible over ground suitable for their action, i.e. reasonably hard soil which had not been shelled to pieces. The area chosen was that near Cambrai, in the re-entrant of the Canal d'Escaut between Ribecourt, Crevecoeur, and Banteux, which consisted of almost unshelled rolling downs of chalk. The attack was originally intended to be of the nature of a " raid " (this was not adhered to in its execution) carried out by an advance at dawn of three lines of tanks, the first of which would make straight for the enemy's guns, previously bombed from the air, to be followed up by the second and third; artillery cooperation to be confined to counter-battery work and the destruction of communications and depots, etc., behind the German front line. The essential points of the plan were surprise and speed. The project was put forward and approved, and the result was the battle of Cambrai, which took place on Nov. 20.2 The action as fought was in almost every detail the execution of the plan put forward officially for the employment of the tanks_ by Col. Swinton in Feb. 1916, 22 months previously.

Further details of the plan were that the artillery barrage of shrapnel and H.E. shell should open on the enemy's outpost at zero hour (6 :20 A.M.) and be advanced by stages of 250 yd. just ahead of the tanks and concentrated on special points. The tanks were to go forward at zero hour in sections of three machines, sections being allotted to different objectives according to the strength of the latter. Each section was composed of one vanguard tank and two main body tanks. The former was to lead and protect the advance of the two other machines, behind which followed the infantry in parties of varying size, marching in sections in single file. As the Hindenburg trenches, some 12 ft. wide, would have to be crossed each tank was to carry a specially made fascine to ft. long and 42 ft. in diameter to drop into the trenches to assist in the crossing. Special machines were fitted with drag grapnels in order to drag aside the wire entanglements which were known to be exceptionally thick and strong, for the passage of the cavalry. Great precautions were taken to maintain secrecy, upon which so much depended, and extremely careful preparations were made in the way of reconnaissance, the training of the infantry to act with the tanks, the movement of machines, and the formation of dumps of the necessary stores. For instance the preliminary movement of the tanks necessitated 36 special trains, and the material collected in dumps included 165,000 gal. of petrol, 55,000 lb. of grease, 5,000,000 rounds of S.A.A. and 54,000 of 6-pdr. ammunition. Three brigades (nine battalions) of tanks took part in the attack, with two army corps of three divisions of the III. Army, a cavalry corps and 1,000 guns. In all there were 378 (Mark IV.) fighting tanks and 98 administrative machines.

Fog on the morning of Nov. 20 assisted the attack, which was carried out as arranged, the tanks following the barrage and the infantry the tanks. The operation was an amazing success and came as an absolute surprise to the enemy, most of whose infantry were panic stricken and bolted or surrendered, the garrisons of certain strong points alone offering a determined resistance. Assisted by the tanks, the infantry by evening had occupied Marcoing,' Bois des Neuf, Premy Chapel, Havrincourt, Graincourt, Aneux, Noyelles. Next day, and on the 23rd, 25th and 27th, further progress was made, but the tank units which had been fighting continuously were disorganized and the crews physically exhausted; and the mistake had been made of not keeping a small proportion of tanks in reserve. On the 27th the impetus of the attack died out with practically no more ground gained than had been won on the first day, where the tanks, starting from a base of 13,000 yd. length, had in 12 hr., and at a cost of some 4,000 casualties, enabled the enemy's zone to be penetrated to a depth of 12,000 yd. (at the third battle of Ypres an equal extent of penetration had taken three months), and 8,000 prisoners and too guns to be captured. And their action had obviated the necessity for a preliminary bombardment (which would have cut up the ground and rendered any rapid advance of infantry impossible, and brought a concentration of enemy's reserves), and also the usual wire cutting artillery fire, which together would have cost many millions of pounds. (An estimate places the cost of the preliminary bombardment at the third battle of Ypres at approximately £22,000,000. A similar bombardment at Cambrai would possibly have cost more, as the German wire was on the reverse slopes of the rising ground.) In numbers the of the tank corps employed in the fight amounted to a little over 4,000 of all ranks, or the strength of strong infantry brigade. The fact that there were no larger bodies of infantry ready to reinforce the tired troops and press the advantage gained, and that the cavalry did not break through to Cambrai as was intended, was not owing to any failure on the part of the tanks, which achieved more than had been promised. The absence of any large force to take advantage of the opening made by them tends to show that it was not believed that they could do what they actually did accomplish, and that their complete and extraordinarily speedy success was as much of a surprise to British Headquarters as it was to the Germans. For nearly three years efforts had been made by. both sides to force a way through the enemy's position quickly. At Cambrai a door was suddenly flung open and there was no force to press through. The success achieved by the surprise counterattack by the Germans on the 30th also had nothing to do. with the previous action of the tanks, but its effect was to discount the whole British victory including their performance. Against the southern portion of this German counter-attack a brigade of tanks which were hurriedly collected proved their worth in a defensive role, and gave invaluable assistance in stopping the onrush of the enemy.

The success of the tanks at Cambrai on Nov. 20, and all that it implied, gave as much food for thought as had the first use of gas by the Germans in 1915, unattended, however, by the horror of the means employed on the first occasion when a surprise penetration was effected by either side. It has been described as the " Valmy of a new epoch in War, the epoch of the mechanical engineer:" 2 But it is doubtful if the truth of this 'The information of the capture of this village was sent back by a wireless signal tank, and was received at Albert to min. after the troops entered Marcoing.

War, Col. J. F. C. Fuller, p. 153.

statement has been fully appreciated even three years after the war. Even so, the effect of this action on the Allies, and also on the Germans, was immediate and far-reaching. It almost established the fact, for which the protagonists of the tank had been endeavouring to gain acceptance for many months, that the new Arm, used properly, was a serious factor in warfare which could not be put aside and ignored. And yet, though opinion in regard to the tanks had changed, even at that period when the immense losses suffered in the attempted offensives of the previous eighteen months had rendered the problem of man-power so acute, the crucial point was still not realized that an actual saving in life and economy in man-power would be gained by the development and whole-hearted employment on a very large scale of the mechanical Arm. And steps were not at once taken for a great expansion. The increase of the Tank Corps previously deferred was agreed to; but a proposed further expansion, based directly on the experiences of Cambrai, was not approved. And later, in April 1918, even the agreed increased establishment was again temporarily suspended after the German offensive in order to meet the demands for infantry reinforcements, and was not completed until after the striking successes gained by the tanks in July and Aug. 1918.

After Cambrai all ideas of attempting to prosecute the offensive were abandoned, and there ensued a period of preparation for resistance against the attack which was expected as the result of the reinforcement of the German strength on the west, rendered possible by the defection of Russia. To assist in meeting this, the Tank Corps, now of five brigades, or thirteen battalions, with 320 Mark IV. and 50 Medium A machines fit for action, was in Feb. 1918 distributed in detachments over some 60 m. of front.

During the second battle of the Somme, from March 21 to the end of the month, the part played by it was to coOperate in various local counter-attacks, its action being generally useful in assisting to delay the enemy's advance, as the German infantry would not as a rule face tanks until their guns were brought up. But out of the total, some 170 machines alone went into action usually and inevitably in hasty, improvised operations carried out during the general retrograde movement. Many machines were lost and their crews employed on foot as Lewis Gun sections. It was during this period that the new " Whippet " machines made their debut with great effect. Generally speaking, the tanks were too scattered for full value to be obtained from their action. The corps also took its share in repelling the second German thrust against the British, which started in the Lys area on April 9, during which three battalions fought, some of the of the lost tanks fighting on foot as a Lewis Gun brigade. It was in this quarter, near Villers Bretonneaux, that the first duel between tanks - possibly a presage of future warfare - took place.

The lack of decisive results obtained by the small detachments of tanks acting in improvised counter-attacks in the general defensive seems to have revived the lingering prejudices of those who were hostile to the arm, and who maintained that the mass action of Cambrai could never be repeated. However, in spite of this, progress was made in May and June in preparing for the future offensive, the chief point of note being that the, new Mark V. (heavy) tanks, which were a great improvement, on previous models, being much handier and also more mobile, were arriving at the rate of 60 machines per week. On July 4 occurred the action which probably finally dispelled the doubts of the most conservative and reactionary. This was the surprise attack of Hamel, a deliberate offensive and not a defensive counter-attack, in which recently received Mark V. machines. cooperated with the Australians. This fight was an example of a perfectly organized action and of the advantage of previous careful training to act together of tanks and infantry, and was a speedy and complete success, achieved at the low cost of some 70o casualties. One feature was the special power possessed by the new and speedier tank of destroying machine-guns, many of which were rolled over and crushed.

The logic of facts was irresistible, and after this action the cooperation of the tanks was thenceforward. accepted, not only as a useful adjunct but as an absolute necessity, for all offensive operations. On July 17, at the battle of Moreuil, one battalion of tanks cooperated with three French divisions in a most site cessful attack on a similar plan launched after one hour's preliminary bombardment.

July 18, the date of the great French victory of Soissons, marked the turning point of the war. It depended on tanks, and was rendered possible by their proper employment in mass and as a surprise. In fact, as the recent British offensive on a smaller scale had been, it was based on the battle of Cambrai. It was followed by a similar operation, the battle of Amiens on Aug. 8 which opened the British strategic offensive.

This battle was also based on the power of the tank arm, and was designed and organized to derive the utmost value from it and to give it every chance to perform its proper, logical function in a general operation. The tactics to be employed by the tanks were an elaboration of those employed at Cambrai modified by recent experience and adapted to the improved machines available. The attack was carried out by three army corps, with three divisions in reserve, a cavalry corps and i r tank battalions. In regard to the tank battalions they were now better equipped than they had been. Nine were equipped with the new Mark V. machines (36 each), and two with the " Whippets " (48 each), or in all 420 fighting machines. There were also 42 tanks in reserve, 36 supply tanks, and 22 guncarriers, or 580 machines in all. The " Whippet " tanks were to act with the cavalry. There was no artillery bombardment, and the tanks advanced with the barrage at " zero" hour. The heavy guns were used for counter-battery work and the field artillery moved forward in close support of the infantry. Noise barrages (made by low lying aeroplanes) were used to drown the sound of the tanks approach. On the first day the maximum advance of the tanks was 72 m., and they continued in action for four days till the I ith.

The battle of Amiens was a tremendous blow, both material and moral, to the Germans, who, besides casualties, lost 22,000 prisoners and 400 guns; and the victory was admittedly very largely due to the tanks. Amongst other lessons learned it was again found that these machines, like other arms, required a reserve to keep up the pressure after the first day of action, and that the limit of endurance of the heavy machines before overhaul was three days; that they were suited for trench warfare, the medium machines for open warfare; that the heavy supply tanks should be replaced by a light cross-country tractor; that wireless and aeroplane communication, as then developed, was not so certain as that by galloper; that it was a mistake to tie up tanks to cavalry, for, during the approach they could not keep up, and during the fight were kept back by the cavalry, which under hostile machine gun-fire had to retire or move to a flank until the tanks disposed of the machine-guns; and that machines of greater speed and greater radius of action were necessary. According to one authority,' if machines capable of moving at 10 m. an hour with an endurance of some ioo m. had been available, the German forces south of the Amiens - RoyeNoyon road might have been cut off and the end of the war greatly accelerated.

July 18 and Aug. 8 were not only victories for the French and British over the Germans, they were victories over their opponents for the tank arm in each army. In regard to the British it is sufficient to say that up to Nov. 5, their last fight, no attack took place without tanks. They cooperated in every offensive including such important operations as the battle of Bapaume, and the second battle of Arras, the battles of Epehy, Cambrai-St. Quentin (when the Hindenburg line was broken), the Selle and Maubeuge. Latterly, indeed, during the " war of movement " which set in after the Hindenburg line had been passed, advancing infantry when faced by the German rear-guard machine-gun posts almost invariably halted for tanks to come up and dispose of them before they moved forward.

So far as statistics can show what a part they played, the following facts speak for themselves: By the time of the battle of Amiens much of the personnel of the Tank Corps had been in action 15 or 16 times, and during the 95 days from that time to the Armistice tanks (to the number of 1,993) were engaged in fighting on 39 days. The casualties, killed, wounded and missing were 598 officers and 2,826 other ranks. These, though heavy in relation to the strength of the unit, which was under that of an infantry division, were not heavy for 39 days hard fighting if it be borne in mind that in pre-tank days it was not unusual for an attacking division to suffer 4,000 casualties in one day often without reaching the objective.

The final despatch of the Commander-in-Chief of the British 1 Tanks in the Great Mil); Col. J. F. C. Fuller.

armies contained the following words: - ... Since the opening of our offensive on August 8th, tanks have been employed on every battlefield, and the importance of the part played by them in breaking up the resistance of the German infantry can scarcely be exaggerated. The whole scheme of the attack of August 8 was dependent upon tanks, and ever since that date on numberless occasions the success of our infantry has been powerfully assisted by their timely arrival.

. " It would not be too much to say, that in spite of any artillery assistance, the series of overwhelming, immediate and economical (both in life and treasure) victories won at Amiens and afterwards would have been absolutely impossible without tanks, as would the whole scheme of the strategic offensive which depended for its execution and cohesion on the prompt and certain success of these attacks. And this statement, which is tantamount to an expression of opinion that human bodies cannot vie with armoured machines against wire and machine-guns, is no disparagement of the British infantry. It is one which would be borne out by the survivors of Neuve Chapelle, Loos and the Somme.

After the action of the Somme a few tanks were at the end of 1916 despatched to cooperate against the Turks in Palestine, where the situation was somewhat similar to that which had arisen on the western front. It was doubtful, at first, whether the machines, some parts of which wore out very quickly, would operate in the sandy desert; but it was found that the dry sand was less harmful than the mud of Flanders, and the tanks in fact stood the test well, and covered a surprising number of miles, though they happened to be machines already partly worn out in training. Only eight tanks were sent out, which was far too small a number to enable any very important result to be obtained in a field where the bold use of tanks in force might have had a decisive effect. The terrain favoured their action, and the strength of the defence, doubtless owing to German influence, lay largely in machine-guns. Their entry into action was not a surprise, for the enemy were aware of their arrival in the country; and they were used on two occasions only, at the second and third battles of Gaza, on April 17 and Nov. i 1917, all the machines taking part.

Though the tasks set before them at both battles would have been more suitable to a force of machines five times their number, they rendered in each case great assistance and saved much loss of life. As a result of their help, which was greatly appreciated by the infantry, who were, of course, chiefly affected, an effort was made early in 1918 to obtain a number of " Whippet " machines for action against the Turkish rear-guard during the further advance. But this demand synchronized with the German offensive on March 21, and no machines could be spared for a theatre peculiarly suited to them.

So far an outline has been given of the main tank operations, and the development and expansion of the unit. The former showed a gradual increase of the scale on which recourse was had to the machines, and an elaboration in the preparations made and the tactics applied. From the 49 fighting tanks which were allotted to the attack at Cambrai, the number rose to 580 of all types at Amiens nearly two years later, the latter being the greatest British tank action fought. And, according to the preparations which were being made at the time of the Armistice, any great offensive in 1919 would have been conducted with thousands of British tanks alone, leaving out of consideration the equally large numbers of French and German machines that would have been engaged.

By Aug. and Sept. 1918 the type of heavy fighting machine had been improved in design, reliability and speed, and a faster medium tank had been introduced. Measures had also been taken to equip, for cross country work, all the battle services for the tanks. There were fighting tanks; supply tanks, to carry up ammunition, drinking water and stores; gun-carrier tanks, used for the same purpose, as well as for conveying artillery and trench mortars, both sometimes dragging sledges similarly loaded; wireless signal tanks; salvage tanks; all working on a coordinated system toward the maintenance or pressure on the enemy with the maximum of efficiency. And to assist in doing this there was a complete repair organization, the central workshops, with its advanced stores and salvage companies. For a major operation, the system of attacking with a small number of machines divided up into separate detachments had been abandoned and the proper tactics of mass attack in as large force as possible in definite formations to meet different conditions, with reserves to keep up the advance, had been adopted. Signal units had been formed. The elementary system of signalling with flags and with daylight lamps to aeroplanes had been elaborated, pigeons were used, and wireless signalling had been reintroduced, and wireless telephony with aeroplanes had been tried, but not with much success. Intimate cooperation with low-flying aeroplanes had been organized, especially in the direction of noise barrages, machine-gunning and bombing the enemy, chiefly of the hostile guns, and dropping information, as also observation for counter-battery work, and smoke-screens were employed. In short the battle was organized to include and harmonize with the new instrument.

In regard to the future of the tanks, had the war not ended in 1918, certain proposals for expansion for the 1919 campaign, made at the Inter-Allied Tank Committee in Jan. 1918, were again brought up in July, and new establishments for the increase of the Tank Corps to a strength of 34 battalions were sanctioned in Oct. This strength, together with the number of some 6,000 machines which it was hoped to produce for 1919, is in itself evidence of the importance attached to the tank arm at the close of the war. Its strength in the field in Oct. 1918 amounted to 12,355 of all ranks, whilst many thousands more were under training at home.

The work of designing and producing the different types of machines which took the field, or were almost ready to do so, necessitated a very large organization. In addition to the Medium Mark A. (Whippet) machines, of which, as has been stated, delivery began in France at the end of 1917, the following types were evolved.

designed so as to be made up of parts manufactured in England and the United States, and was to be engined either with the American 30o-H.P. Liberty, or the British 30o-H.P. Rolls-Royce, engine. The engine-room was separated from the fighting-chamber by a bulkhead and the ventilation was improved.

The Mark IX. tank (Infantry tank). The design for this was begun in Sept. 1917. Thirty-five machines were made, but none was actually used. It was a long machine with space in the centre to carry 50 infantry or 10 tons of stores.

The Medium B (Whippet) tank. The design of this, which differed from that of the Medium A, was commenced in June 1917. The shape was more like that of the heavy tanks. It had a four-cylinder 150-H.P. Ricardo engine. Forty-five machines were made, but none used. In all, 2,636 British tanks were constructed.

The production of the tanks on the first order for i so which, were in action in 1916, six months after the order had been placed, was, as has been said, a remarkable achievement. After that time supply was carrried out by the Mechanical Warfare Supply Department of the Ministry of Munitions, working in conjunction with the War Office and G.H.Q. in France. The subject was handled by a succession of committees, composed of those concerned, which endeavoured to obtain cooperation and the allocation of responsibility as between the army, which demanded machines and changes of design, etc., and those who had to meet these demands. In Aug. 1918, control was taken over by a Tank Board, to coordinate all sides of the question of supply. There were naturally considerable difficulties in administration of the production side of this weapon improvised during hostilities, at a time when the manufacturing resources of the country were already deeply committed in satisfying the FIG. 8. - Mark V. Tank.

r°--t ? ° The Mark V. tank (see fig. 8 and table A). This was in design and size the same as Mark IV., but it was superior to it in the following particulars: - The engine, a 6-cylinder Ricardo engine of 150 H.P., was more powerful and was expressly designed for the tank. The manoeuvring powers were improved by one-man control and an epicyclic gear. The means of observation were improved. The unditching gear could be worked from inside the machine. Better means of clearing the tracks of mud were provided. The design for this was begun in Oct. 1917 after the experiences of Messines and the third battle of Ypres, and was to meet the requirements as then known. Some of these machines reached France in time for the attack on Hamel on July 4 1918, and this tank was the principal machine of all the subsequent fighting. In all, 403 were made.

The Mark V. Star tank was the same as a Mark V. machine, with 6 ft. added to the middle of its length. It could cross wider trenches (14 ft.) than the Mark V. machine, and could carry about 20 men in addition to the crew. The design was not started till Feb. 1918, 32 machines being made, of which some were delivered in time for the battle of Amiens. The tank was too long to be very handy.

The Mark V. Two-Star tank was the same as the Mark V. Star, but with a 225-H.P. Ricardo engine. Design was started in May 1918, one being made but not delivered before the Armistice.

The Mark VI. tank was intended to be the same size as the Mark IV. with an improved transmission (the Williams-Janny variable speed gear), but did not get beyond the design stage.

The Mark VII. tank. This was 3 ft. 6 in. longer than the Mark IV. and Mark V. It had a 150-H.P. Ricardo engine and a variable speed gear. Seven were made, but none was used in the field.

The Mark VIII. tank. The design for this machine was commenced in Dec. 1917; seven machines were made, but none was employed in the field. It was larger (34 ft. 21 in.) than any other tank, and was urgent demand for munitions of other kinds. The lack of continuity in the demands, also, which fluctuated as the value of the tank varied in the opinion of the army in the field according to its success in action, made continuity of work and accurate forecasts of output almost impossible. There were also questions of obtaining the necessary labour, manufacturing facilities, raw materials, and that of priority amongst so many competing requirements for carrying on the war. The problem was complicated by the multiplicity of special component parts and fittings required, the great wastage of machines from action in the field, and the quite unexpected wastage by wear and tear of certain parts, some of which, as the design of the machines developed, became obsolete before they could be used; and there were the technical difficulties of ensuring efficiency in details, of which the only test could be use in the field.

A great expansion in the sources of supply became necessary as the programmes of construction increased in size, and many engineering firms were engaged in the manufacture of the tanks in addition to the comparatively small number concerned in 1916 and 1917. Before the Armistice the supply of tanks was considered so important that men were relieved from the army to carry on production. The programme for 1919, including Inter-Allied production, which covered over 6,000 machines, required 193,000 tons of steel, 10,000 6-pdr. guns and 30,000 machine-guns, and an expenditure of £80,000,000. By the end of the war, tanks were accepted as being the best and most economical means of arriving at a decision in the field, as the ratio of results obtained to material and man-power absorbed was greater than from any other means. In England development in design has since continued in the direction of the evolution of tanks possessing greater speed and a greater radius of action than that of the more or less embryonic machines which were evolved during the war, and also in the production of machines which can function either on land or on water. Success in these directions will endow the machine, originally improvised with the limited object of assisting the infantry to break through an entrenched line, with far greater powers.

French Tanks It is not remarkable that allies fighting a common enemy, side by side in the same theatre of war and subjected to similar conditions, should have evolved a similar means of meeting them. And it would have been natural had they done this simultaneously, in a common effort, or at least with mutual knowledge from the beginning on the part of each of what the other was doing. Curiously enough, this was not the case with the British and French, the two nations concerned in the creation of the tank. Forced into being by the same causes, a remedy for the same disease, even suggested in form by the same mechanical prototype, the British tank and the French Char d'Assaut were conceived separately, and for many months developed on independent lines, the British ignorant of French intentions and the French ignorant of what the British were doing. In the case of the latter, as of the former, it was the difficulty experienced in carrying out the pre-war theories of infantry attack against a prepared defensive which finally led to the new machine, though the effect of the H.E. shell of the French field gun may have prevented its necessity being felt so soon.

The French owed their tank 1 to the foresight and pertinacity of Col. (later Gen.) J. B. E. Estienne of the artillery, who, during the retreat of 1914, perceived the desirability for having some means of transporting infantry under cover across obstacles and swamps and ploughed land. Later, during the summer of 1915, on seeing the caterpillar gun tractors in use in the field by the British, his ideas took a more concrete shape in the direction of a cuirassc terrestre (land battleship). This was to be a caterpillarpropelled machine 4 metres long, 2.60 metres broad, 1 60 metres high, weighing nearly 12 tons. It was to be provided with a petrol engine, to travel at a speed of 6 m. per hour on the flat, to be protected by armour up to 20 mm. in thickness, to carry an armament of two machine-guns and one light Q.F. gun for the attack of machine-guns behind shields, and to be capable of crossing trenches two metres wide and forcing its way through barbed wire. It was also to draw an armoured trailer carrying 20 men and equipment. This was worked out in greater detail, but was in essentials the same as the scheme put forward in England in Oct. 1914, except that as projected the cuirasse was to be somewhat of a hybrid between a tug to haul a transport filled with men and a fighting machine, and not purely a destroyer which would open out a way for men to advance on their feet. Actually, however, both types were developed as fighting machines. Both, also, were inspired by the Holt tractor, of the existence of which the British originator had knowledge before the war, and of which the French originator first became aware when he saw it at work behind the British lines. Before these machines were introduced by the British in the early part of 1915 for moving heavy artillery, tractors on the caterpillar system were practically unknown in France. Later some brought over from Tunis were employed with the army of the Vosges. After communicating with the commander-in-chief, Col. Estienne on Dec. I 191 put forward his ideas in an official letter with a request for an interview. This took place on Dec. 12, which date can be taken as marking the official conception of the French tank. After consultation between Gen. Jofre and Col. Estienne, and discussions between the latter and representa 1 For convenience the word " tank " will be used generally to describe the French machines.

tives of the Renault and Schneider works during Jan., the French Army H.Q. submitted to the Ministry of War a demand for 400 tanks. These were to be of the design prepared jointly by M. Brille of the Schneider Creusot Works, and Col. Estienne. For the French, therefore, this was the commencement of the solution of the problem of mobile protection for the infantry.

In regard to the French tanks, the year 1916 can be taken as one of gestation. The year 1917 covered the birth and infancy of the medium (Schneider and St. Chamond) tanks; the first half of 1918 the adolescence and maturity of the medium machines and the birth of the light (Renault) tank; and the last half of 1918 the adolescence and maturity of the light machine. But the period of gestation before the birth of the new arm, i.e. the appearance in the field of the Artillerie d'Assaut, or " A.S.," was, as in the case of the British Tank Corps, somewhat lengthy. Its promoters still had much opposition and many obstacles to overcome, for the question of production was handled by more than one department or directorate, a state of things which is usually bound to result in friction and delay. It appears, also, that whilst some officials were impressed with the vital urgency for expedition others were more concerned to conduct matters in accordance with the regular routine of peace procedure. But there was no intervention by an outside department or ministry to save the situation. It is not on record that the French Ministry of Marine collaborated in the creation of the Chars d'Assaut. On Feb. 25, after some inter-departmental discussion and trials of a baby Holt tractor, and without waiting for the construction of any experimental machine, an order was placed with the Schneider firm for 400 tanks, then called tracteurs Estienne, afterwards known as Chars Schneider, to be delivered within six months. This was only two weeks after orders had been placed by the British for the first loo Mark I. tanks. So far the comparative progress in development of the new arm by the two nations had been as follows: - the idea of the tank had occurred at about the same time to both; the matter had been put forward officially by the British in the third month of the war and by the French 14 months later; the first actual order for machines, given by the British 18 months after war began, was followed by that of the French only a few days later. The British machines, however, took the field six months before those of their Allies. In addition to the 400 Schneider tanks a contract for 400 more machines of a different type was placed with the St. Chamond Works in April, without the knowledge of the commander-in-chief or of Col. Estienne.

Not long afterwards steps were taken for the formation and training of personnel for the new arm at Marly-le-Roi. In June French H.Q. received from British G.H.Q. official intimation of what was being done in England. Col. Estienne visited England, and after inspecting the Mark I. tank in the training area at Elveden reached three conclusions. One was that the two countries should collaborate in the production and cooperate in the use of the new weapon in the field. The second was that neither should forestall the other in employing it and so discount its maximum value for the Allies as a whole. On this Col. Estienne was specially insistent, because it was apparent that the British were far ahead in production and would probably be ready before the French. The third was that. as a complement to the heavy, somewhat slow, British tanks, capable of negotiating almost any obstacle, the French should specialize in the production of a speedier and more handy machine, which would be to the British tank what field artillery is to heavy artillery, would perform the duty of a swarm of skirmishers in armour armed with a machine-gun, and would be capable of going wherever an infantry soldier could go. The scheme for light tanks did not meet with a favourable official reception, and sanction for the construction of 50 machines of this type was not given. Nevertheless designs were put in hand by the Renault firm and at the end of Nov. were so far completed that construction could have been started. Though no executive action was taken for some months, except that 150 machines for use as " command " tanks for the units of the Artillerie d'Assaut were given, this was the genesis of the Renault tank.

The French classified tanks in three categories: Chars legers, machines weighing under 10 tons.

Chars mediums, machines weighing io to 30 tons, which could be transported by rail on ordinary trucks.

Chars lourds, machines which would require specially constructed trucks for transport by rail.

As the medium tanks were the first constructed and used, their description will be given first. Both the Schneider and St. Chamond tanks were smaller and lighter than the British Mark I. or any subsequent pattern of heavy machine, and were, according to British nomenclature, males. The great difference between them and the British heavy tanks was that the designers of the former, in taking the caterpillar tractor as a model, had been content to employ tracks somewhat similarly placed under the body of the machine, and not extending all round it as in the case of the British heavies. The tracks were also shorter FIG. 9. - French Char Schneider.

than the full length of the body, instead of projecting well beyond it, at least at the front, as was the case with the British Whippets, and the French Renaults, and both tanks had a particularly " underhung " appearance. It was this arrangement of the tracks which militated against the climbing powers of the machines, whilst their comparative shortness limited the spanning powers across a trench.

The Char Schneider (see fig. 9) was 6 metres in length, 2 metres in width and 3.40 metres high. It consisted of an armoured body resting on two horizontal girders with the necessary bracing. The weight was taken by springs on two bogies on each side, which were carried by the track rollers. The track was actuated by a driving sprocket at the rear, there being an idle wheel at the front. The gearbox was at the rear, the radiator in front. Power was given by a fourcylinder Schneider engine of 60 horse-power. The petrol feed was by pressure. Steering was effected by driving the tracks at different speeds. The whole body formed a box of somewhat peculiar shape protected by hardened steel plate of 11.4 mm. thickness on the walls and 5.4 mm. on the roof. There were various openings with movable shutters for observation, etc., and the door was at the back. In front was a steel prow, or beak, to prevent the machine dipping too much when descending into a cavity. The armament consisted of one short 75-mm. gun, of a maximum useful range of 600 metres, mounted on the right cheek of the bows of the machine which could from its position fire only on the right side and not directly ahead. There was also one Hotchkiss machine-gun on each side firing through a spherical shield mounting. For the gun 90 rounds of ammunition were carried and for the machine-guns 4,000 rounds. One officer, one N.C.O., and four men, of whom two were machinegunners and one a gunner, formed the crew. The officer drove. The total weight of the machine was 13.5 tons and its useful speed from 2 to 4 km. per hour. It could cross trenches of from I. 50 metres to 1.80 metres in width, and carried petrol for 6 to 8 hours' work.

The Char St. Chamond (see fig. 10) was a larger and heavier machine. It was 7.91 metres in length, 2.67 metres in width and 2.365 metres or 2.35 high, according to the pattern. It consisted of an armoured body in suitable framework suspended on spiral springs on three bogies on each side, which were carried by the track rollers. The drive was through the rear sprocket. The driving mechanism was petrol-electric and consisted of a four-cylinder Panhard engine of 80-90 H.P. with electric self-starter, a dynamo of 52 K.W. power and two electromotors, one driving each track. Driving was done by a " tramway " -control, by which speed and direction were regulated. This system had great conveniences, for the machine could be driven from either end without effort, but it had the drawback of being somewhat complicated and delicate. The petrol feed was by pressure, and the tanks were two superimposed on the left side and one on the right. The whole body formed a box with a square sloping front without any beak. It was enclosed in hardened steel plate of I 1 mm. thickness in the front shields, and 8.5 mm. at the sides and 5 mm. on top. On the roof there were three observation cylindrical capots with sides of I I-mm. steel above the commander's and driver's ports. The doors were at the sides. The armament consisted of one 75-mm. field gun, except in the first 175 machines which had a special gun, firing ahead in front, and four Hotchkiss machineguns, one in front to the right of the gun, one on each side and one on the rear face. For the gun 106 rounds of H.E. were carried and for the machine-guns 8,488 rounds of S.A.A. The total weight, loaded, was 24 tons, and its useful speed on the flat 8.5 km. per hour. It could cross trenches up to 2.50 meters in width in good soil. The petrol carried was enough for from 6 to 8 hours. The crew consisted of one officer, one N.C.O., two gunners, four machine-gunners and one mechanic, or nine in all.

During Sept. the first tank of each type arrived at the training centre, where a considerable number of officers and men from different branches of the Service had already collected for preliminary individual instruction. An additional training centre for the formation of units was established at Champlieu, and also a depot for the assembly of materiel at Cercottes, near Orleans. It was then decided, also to create the new "Artillerie d'Assaut " and the charter of this organization may be said to date from the 30th of that month. Col. Estienne was promoted to the rank of general, and was appointed " Commandant de l'Artillerie d'Assaut aux Armees" and representative of the commander-in-chief in tank matters with the Ministry of Munitions, which department had been created and taken over tank production. In Oct., with the arrival of more machines of both types, the Artillerie d'Assaut started on its career. It seems that the use of the British tanks at Cambrai, which had been deprecated by the French beforehand, and criticized for the reasons already stated, may have stimulated the French to press on with their own service, though what had been looked upon as the supreme factor of surprise had been discounted.

FIG. io. - French Char St. Chamond.

The work of preparation, including training and equipment, continued throughout the winter, in preparation for the offensive to be undertaken in the spring of 1917. On March 31 1917, the organization of the Artillerie d'Assaut' was as follows: The tactical unit, under a captain, was the groupe, which was divided into four batteries, each consisting of four tanks. A groupe, therefore, comprised 16 tanks with a special " command" light tank (Renault). For a Schneider tank groupe the establishment was 18 officers and 92 other ranks, for a St. Chamond tank groupe 18 officers and 106 other ranks. A groupement consisted normally of four Schneider or three St. Chamond groupes, but was not rigid. For repair work each groupe had its own workshop and a Section de ravitaillement et de reparations 1 Why this arm was ever called " artillery " is not clear. Its closer connexion with, and resemblance to, infantry was recognized later, and the names of the elements of the organization for the light tanks followed those of the infantry, e.g. battalion, company, etc.

(S.R.R.), of r officer, iii other ranks, was allotted to every io groupes. There was for the whole unit a Section de pare, or repair park, similar to that of the Mechanical Transport Service. This was found necessary so soon as tanks had been delivered in any number, owing to the amount of tuning-up, minor repair work and even alterations which had to be done.

Numerous faults at once developed in these entirely new machines (as had been the experience of the British), but thanks to the time available before they went into action, certain defects were discovered and remedied. The first was that some parts of the machines wore out very quickly, necessitating the maintenance of a very large stock of spares. The thickness of steel plate where vertical was not proof against the German " K " bullet, and it was found necessary to add an outer plate of 5.5 mm. to the vertical armour of the Schneider machines, and 8.5 mm. to that of the St. Chamond machines. On the whole the defects discovered in the Schneider tanks were not such as to give reason to suppose that they would not be able to go into action in the spring; but those of the St. Chamond were more serious. The design was found clumsy and the machine liable to ditch. In addition to breakdowns in the power system and failure in details, there was a lack of rigidity in the whole machine, and the tracks of the first machines were too narrow.

Delivery of both types was extremely slow, especially of the St. Chamond machines. At the end of March, though personnel for 15 of the latter was ready, there was not one machine serviceable. At this time, on the eve of the great r9r7 offensive of which so much was expected, the Artillerie d'Assaut, instead of being in possession of the 800 tanks which were to have been ready by the previous autumn, had received not more than 208 Schneider and 48 St. Chamond machines. There were for this operation, therefore, only 8 fully and 2 partly trained groupes of Schneider and r of St. Chamond tanks, and not 40 groupes as originally contemplated; and of the 160 Schneider machines only one had been fitted with the extra bullet-proof protection. In view of the diminution of the tank force from what was expected to be available, and with the example of the result of the action of the British in the previous Sept. before it, the French High Command had grave doubts whether to make use of tanks in the coming operations or to wait until there should be sufficient to exercise a greater influence. It was finally decided to throw all possible weight into the attack.

April 16 was the baptism of fire of the French tanks, in Gen. Nivelle's unsuccessful attempt to break through the German line along the Chemin des Dames, E. of Craonne.

Eight Schneider groupes cooperated with the French V. Army. They were divided into two parts of three and five groupes respectively. One party did not succeed in crossing the German line, though a few machines reached it, and it suffered severely from the enemy's guns posted on the Craonne Plateau. The other party succeeded in crossing the enemy's second line, but were not followed up by the infantry, owing to the German machine-gun fire. Two Schneider groupes and one St. Chamond groupe allotted to the French IV. Army for employment on the 17th were not thrown into the fight, as the German artillery observation posts were not first captured by the infantry - a lesson of the action of the 16th. The offensive failed; and though the new arm showed the utmost devotion and gallantry, and its intervention saved many lives, it did not achieve the success that was hoped. But the conditions were almost as unfavourable for the employment of tanks as they could be, and the tactics employed were not those urged by those responsible for the new arm. The attack was not a surprise, being preceded by a heavy bombardment, which, however, did not succeed in overcoming the German artillery, and was made in broad daylight, without any smoke-screen, against a position which permitted of direct observed artillery fire against the tanks both when approaching and when they reached the enemy's positions. The plan, also, in which certain infantry units had been trained to cooperate, was that the tanks were to attack the German third defensive line after the infantry should have gained the first and second, and were not to advance until after this had been achieved. The Germans, who were prepared for the attack, therefore, had even additional time before the tanks appeared, and the result was that their guns caught many of the machines in column before they deployed..

The machines themselves showed certain faults - they were deficient in speed and climbing capacity, the latter defect being accentuated by the fact that since the Somme the Germans had increased the width of their trenches. They also proved, as was known before would be the case, vulnerable to direct hits of H.E. shell, by which many machines were set on fire. Amongst other points of design in which modification was found necessary was that of isolating the petrol tanks from the interior of the machine, improving the means of communication, the power of observation, the ventilation, and various details of mechanism, and of widening the tracks. On the whole the Schneider machines stood the trial best. In. the next tank attack, carried out on May 5 by the VI. Army, the battle of Laffaux Mill, the three groupes employed advanced with the infantry with marked success, especially in the case of the Schneider machines. The counter-battery work of the French was good and the enemy observation posts were destroyed or masked; and the tanks did not remain too long in advanced positions where the infantry were checked.

For nearly six months the tanks did not again go into action. During this period great efforts were made to remedy the defects disclosed, to expedite the delivery of machines, which was much in arrears, and of spare parts, the demand for which (as in England) had been found very greatly to exceed any anticipations, and to augment the establishment of repair units. In preparation for the next operation great care was taken in the training of infantry with the tanks in attack and in tank tactics generally. On Oct. 23 five groupes of tanks took part in the battle of La Malmaison along the Chemin des Dames. Their assistance was most valuable.

Owing to previous heavy rain, and the bombardment which had continued for six days and six nights, the ground was extremely difficult, and in the centre the tanks were not of so much help in the first phase of the attack as later. This state of the ground and the lack of surprise again discounted to a great extent the preparatory training undergone by the units of the Artillerie d'Assaut. The practice which had been carried out beforehand with the attacking infantry, however, proved of great value, as did the work of the special unditching sections. The ground had been carefully reconnoitred and aerial photographs supplied. The Germans relied on this occasion more on their advanced field guns for defence, and had also organized numerous special machine-gun posts furnished with plentiful supplies of armour-piercing ammunition. But owing to the counter-battery work of the French the tanks were not so much damaged by the German guns as in April, in spite of the fact that the attack was not a surprise. Two days later some St. Chamond machines again operated with success.

Apart from the projected light tanks, the necessity for an improved medium tank had been realized before April 1917, and the subject was under consideration throughout the year. The main directions in which the April offensive showed improvement to be necessary were the desirability of mounting the gun in a: turret to give all-round fire, of mounting a 75-mm. field gun in place of the shortened 75, and of increasing the size of the. tracks and the power of the engine. Designs for a new medium machine (C.A.3) were prepared in Aug. 1917, but were abandoned after the battle of La Malmaison because the further improvement then found desirable, i.e. the provision of 6 to 7 H.P. per ton weight, a trench-crossing capacity of 3 metres, and an ability to climb ahead or astern, showed that the designs were already out of date, and would be more so by the time the machines could be made. At the end of Oct. it was decided to suspend the construction of an improved type of medium tanks and to concentrate on that of the light machines; and in Dec. the idea was finally dropped. The question of providing heavy tanks was taken up at the end of 1916 as a result of the operations of the British machines in Sept., and in order to have available a machine which would be complementary to the light tanks it was hoped would be made. A project was put forward for a heavy tank weighing 38 tons to carry a r05-mm. gun, but its execution was postponed in view of the demands that might be made for other machines. Two experimental heavy tanks, one with mechanical and the other with electrical transmission, were tried, and it was decided to investigate in the direction of still heavier machines.

In regard to the type which will always be especially associated with the French, the Char leger, or Renault tank, first suggested by Gen. Estienne in July, and for which designs were prepared' in Nov. 1916, the commander-in-chief in that month expressed his desire for r,000 of such machines. But whereas those responsible for supply had, in the case of the medium tank, pressed forward the construction of one type, the St. Chamond, without military approval of the design, in the case of the Renault every obstacle seems to have been placed in the way of manufacture of this machine, for which army H.Q. and the Artillerie d'Assaut were pressing throughout the winter, though various trials were made. In March 1917, the demand of army headquarters was increased, being based on the requirements for an offensive on a loo-km. front. This entailed the production of 3,000 light, 400 medium (improved Schneiders) and 150 heavy tanks. In May an order was given for i,000 Renault machines in addition to 150 which had been ordered in March as " command " tanks. Discussion as to design, armament and manufacturing facilities and trials continued during the summer of 1917. In Oct. it was settled that in addition to the 1,150 already on order, 2,380 more should be made, or 3,250 in all, the work being distributed between four French factories, the whole to be delivered by the end of July 1918. Of the total, 1,000 machines were expected to be ready by March 31 1918, for the contemplated offensive in the spring, and i,000 were to be manufactured in the United States, of standard American parts and equipped with Liberty engines. The decision to devote so much money as this entailed and so much of the manufacturing power of the nation at a moment when the demands for munitions of war of other kinds was at its height illustrates the importance now attached to the new arm. The British success at Cambrai seems to have had considerable effect in influencing those who were still sceptical of the value of the tank and of the wisdom of relying on it for future operations. In Jan. 1918 a supplementary order was placed for 470 machines, the final total figure fixed for production in France being 4,000, divided into i,000 armed with machine-guns, 1,830 with the 37-mm. gun, 200 signal tanks, and 970 for a reserve armed with the 75-mm. gun.

The Renault tank differed greatly from the Schneider and St. Chamond machines. Not only was it considerably smaller, but the tracks were outside the body and not underneath it and extended to a considerable distance in front. Its total length, without the movable tail, was 4.100 metres; its breadth 1-740 metres, and its height 2.140 metres. The body was supported on hollow longitudinal girders by a hinge arrangement at the rear end and suspended on powerful springs in front so that the front of the frame and body were capable of relative movement. Each girder was carried by springs on four bogies supported by wheels running on the tracks. The idle track pulley in front was of larger diameter than the driving-sprocket at the rear and this and the projection of the tracks gave the machine a greater grip in climbing over obstacles. The upper portion of the track ran in spring guide rollers which were arranged to regulate the track tension automatically. The interior of the tank consisted of a driver's compartment in front and the engineroom behind. The crew comprised two, one officer or N.C.O., who was also the gunner, and one man who was the driver. The driver was seated; and also seated, or standing, behind him was the gunner, with his head and shoulders in the turret. The latter revolved on ball-bearings which allowed of all-around fire, and was furnished with a lock and a door at its back. The whole of the machinery, engine, radiator, clutch, transmission gear and petrol tank were in the engine-room, separated by a steel bulk-head pierced by openings closed at will from the driver's compartment. Power was given by a four-cylinder Renault engine of 35 H.P., with the usual transmission. Steering and control could be done by one man. Protection consisted of hardened steel plate 16 mm. thick for the vertical portions (proof against the armour-piercing bullet) and 8 mm. for other parts. The armament was either a 37-mm. Puteaux semi-automatic gun, or a Hotchkiss machine-gun; and 240 rounds including 40 rounds of case shot, or 1,820 rounds of S.A.A. were carried. Fully loaded the female weighed under 62 tons and the male just over 62 tons. There were four speeds ahead and astern giving to the tank a maximum speed on the flat of 7.78 kilometres. It could climb slopes up to 45° and span openings up to 1.80 metres in width, in which it was assisted by the movable tail. This was the machine upon which the French relied for the operations of 1918. The question of the provision of Renault wireless signal tanks was taken up in May 1917, and a machine capable of sending and receiving wireless messages was constructed.

In the autumn and winter of 1917 the reorganization and training of the Artillerie d'Assaut continued with a view to its expansion. In addition to the medium tanks still being delivered, bit was expected, by March 31 1918, to receive Boo of the Renault tanks then due. The establishment of the Artillerie d'Assaut was tentatively fixed as follows: - four groupements (16 groupes) of Schneider tanks, with four repair sections; four groupements (12 groupes) of St. Chamond tanks, with four repair sections; 36 companies of Renault tanks; one groupe depot for Renault tanks; one salvage groupe; three park sections. The number of Renault companies was fixed at 30 before the end of the year.

The organization of the Renault tanks, which were regarded as an infantry arm, was to be by sections, companies, battalions and later by regiments and brigades. A company comprised three sections of five tanks each and an echelon de combat of 10 tanks (of which one was a wireless signal tank),' or 25 machines in all.

A battalion contained three companies of 75 tanks. Changes were made in the administration, and Marly-le-Roi was given up as a training centre, two army group-training centres being established at Mailly-Poivres and Martigny, the training facilities and auxiliary services generally were increased and elaborated, and the relation of the Artillerie d'Assaut to the Ministry of War was defined and simplified. All these preparations were carried out with a view to the cooperation of the tanks in the French offensive in the spring.

When the German advance on March 21 1918 wrested the initiative from the Allies, amongst other results it upset all the plans carefully worked out for the French tanks. Instead of taking part in mass in a great offensive, as intended, whatever tank units existed had now hurriedly to be collected and thrown into the defence. The factor ruling the speed of the creation of the service had all along been the rate at which the materiel was delivered. This, for various reasons, was always much behind the scheduled time arranged. On March 21 the medium tanks in a serviceable state fit for immediate use amounted in number to 245 Schneider and 222 St. Chamond, or 467 machines of an obsolescent type, and of the new Renault tank 1 machine ready for action, with the army. (By the beginning of April over 400 had been turned out by the factories. But these were made up of training machines without armament or armour, pattern machines, machines issued to the American army for training, and those under test.) Moreover the approach of the Germans necessitated the hurried evacuation of the tank centre and main park at Champlieu. And so, not only was the new arm, still in its early infancy, forced to face an entirely fresh situation with improvised measures, but part of its organization was suddenly torn up almost before it had taken root. Great efforts were made both to assist in coping with the immediately urgent necessity of checking the enemy's advance and to prepare for subsequent action. Champlieu was reoccupied in the beginning of April, when the progress of the Germans to the north was checked; but a central reserve park farther from the front, near Fontainebleau, and three others were established.

Operations during April and till the end of May were confined to the medium tanks, which alone were available and mobilized. Four groupements of Schneider machines were allotted to the III. and I. Armies, joined later by three of St. Chamond machines. All the actions now undertaken were, as was the case with the British tanks, of the nature of minor counter-attacks, and not such as the tanks were best suited for. They took place, on April 5, at Grivesnes; on April 7 at Senecat; and on April 8 at Cantigny, the last being in cooperation with the American troops. The most successful was the last, in which the action of tanks had been legislated for. The artillery bombardment was short and portions of ground were left unshelled to allow of the passage of the tanks. Though not actually fighting, the tanks were at this period continually being moved about in readiness, and to save wear and tear the system was adopted of transporting them by road on special " tugs " drawn by caterpillar tractors.

On May 31 the Renault machines received their baptism of fire on the E. of the Forest of Retz. Three battalions of these machines now ready were allotted to the VI. Army, and were brought up by train, on lorries and on tugs. Six sections had to be flung into the fight. Without previous reconnaissance or any liaison with the already exhausted Colonial infantry, who had never seen a tank, they had practically to make a cavalry charge in broad daylight, without a smoke-screen, across a mile 'Owing to delays in manufacture and difficulty in technical training the first wireless signal tanks did not take the field until July 1918, when after some practice they were found of great value. As has been stated British tanks were fitted with equipment and trained operators ready for the field in July 1916.

of open plateau under observation of captive balloons and without effective support from their own guns. One condition favoured their action; their attack was a surprise.

Though the tanks succeeded in clearing the enemy out of their positions, their success had no tactical result, for the infantry could not follow up and consolidate the ground gained. But they caused panic, and inspired a nervousness and hesitation amongst the Germans which was invaluable at the moment. This and their subsequent actions carried out during June served to prevent the enemy from penetrating into the forest.

Meanwhile, four groupements of medium tanks led and greatly assisted Gen. Mangin's counter-stroke at Mery-Belloy on June against the flank of the German salient between Noyon and Montdidier, by which the enemy's progress toward Compiegne was arrested. The tanks played a great part in this operation which had such strategic importance, but this action was the high-water mark in the career of the medium tanks, for they were becoming worn out and were gradually replaced by the new and more efficient Renault tanks as the latter were produced.

By July considerable