1922 Encyclopædia Britannica/Tanks

The name tank was given during the World War to the bullet-proof, armed vehicle, driven by mechanical power and capable of crossing rough country and obstacles by the use of caterpillar tracks. The name was first used 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 the name was universally adopted. 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.

I. THE INVENTION OF THE WEAPON

The Tank Idea in History. —From the earliest times men have attempted to find methods whereby they might move under some form of protection while they delivered blows at the enemy. Vehicles of many different types have been constructed throughout the ages with a view to solving these first principles of war and those vehicles were the forerunners of the tank. The earliest fighting vehicles of which there is a record, date back to 1200 B.C. when the Chinese made use of protected vehicles propelled by man or horse-power and to the use of war chariots by the Assyrians. In the 15th century the Tudor “ war carts ” appeared and fighting vehicles were constructed which were the exact counterpart of the modern tank except in motive power; and numerous examples of fighting vehicles appear throughout history, all aiming at the provision of mobile protection for the fighting man.

The introduction of rifled breech-loading firearms led to the disuse of all forms of fighting vehicle. The weight of armour which was necessary to provide protection was such that no armoured vehicle could be propelled across country by manpower or horse-power. The necessity for a fighting vehicle still existed and was in fact accentuated, especially with the introduction of the machine-gun; there was, however, at the time no apparent solution to the mechanical construction of such a vehicle. As time progressed two inventions were developed and it was the combination of these that led to the construction of the tank. The two inventions were the caterpillar track and the high-speed internal-combustion engine. ‘The former enabled heavy vehicles to cross soft ground by the use of a track or endless belt so that the weight was distributed over a large area of ground; the latter provided a light compact power unit by means of which the vehicle could be propelled. The combination produced tractors such as the Holt, invented and in common use in America before the War. Between 1907 and 1914 several inventors suggested that tractors of this nature should be constructed and provided with armour for use as a fighting vehicle in war. No official action was, however, taken in this direction. The prevailing military opinion among all nations prior to 1914 was that any future war would be mainly a war of movement, and although it was realised that a frontal attack against a defensive position would be costly, it was considered that such an attack would be greatly assisted or even avoided entirely by envelopment or flank action.

The opening phases of the World War appeared to confirm these views, but in Sept. the Germans fell back and took up a defensive position on the Aisne and it was then that the great strength of modern field defences became apparent. The main source of strength of these defences lay in the machine-gun protected by an extensive use of barbed wire entanglements, and they proved to be impregnable to attack by troops, equipped as they were in 1914, without the most prodigal loss of life. The efforts of the British troops early in Oct. to outflank the Germans in the north, led to an extension of these defences right up to the sca. The Allies were then faced with a continuous defensive position without flanks that could be turned and they possessed no means of penetrating such defences. One solution of the difficulty appeared to be a large increase in the available artillery resources, particularly in the larger pieces and the provision of high-explosive shells. This solution was acted on at once and although no result could of course be expected for many months, it was hoped that sufficient artillery and ammunition would eventually be available to blast a way through the enemy defences and so re-establish the power of mobility.

Col. Swinton’s Proposal.—Early in Oct. 1914 an officer of the Royal Engineers, Lt.-Col. (later Maj.-Gen.) E. D. Swinton, Royal Engineers, formed the opinion that a frontal assault against prepared positions, especially with limited artillery support, had become impossible, and that some form of power-driven protected machine which could traverse trenches and barbed wire was necessary to enable the attack to overcome the power of the defence. On Oct. 20 1914 Col. Swinton saw Col. (later Sir Maurice) Hankey, Secretary of the Committee of Imperial Defence, and put forward his scheme which was briefly to develop the Holt tractor and produce a mobile armoured machine which should lead the assault and act as a machine-gun destroyer.

As a result of the interview described Col. Swinton took up the question with G.H.Q. in France and Col. Hankey put the idea before Lord Kitchener; but in neither case did it lead to any result. Col. Hankey however also submitted the scheme to the Prime Minister as Head of the Committee of Imperial Defence, and this reached Mr. Churchill who was already experimenting with armoured cars for the naval detachment of the Belgian coast. On Jan. 5 1915 Mr. Churchill wrote to the Prime Minister emphasising the importance of Col. Swinton’s suggestion. This letter was sent to Lord Kitchener, and at the same time Col. Swinton called at the War Office to discuss his proposals. As a result the matter received some attention and a few trials were carried out, after which the whole question was dropped. In the meantime Mr. Churchill formed a committee at the Admiralty under the chairmanship of Mr. (later Sir) Tennyson d’Eyncourt, to investigate the problem. They carried out trials with large wheeled machines, coupled steamrollers, pedrail and caterpillar tractors, single and articulated, the underlying idea being the production of a machine for the conveyance of troops and not a machine-gun destroyer.

In the meantime Col. Swinton took his proposals to the commander-in-chief in France with the result that the specification of the type of machine required was sent to the War Office. By that time a joint naval and military committee had been formed and they were now able to work to a specification which detailed the military requirements. The result was the production— first of ‘‘ Little Willie ” which just failed to reach the standard required, and later of “ Big Willie” or “ Mother ” as it was christened, which passed all tests at Hatfield on Feb. 2 1915. The chief point in the design, and on which it differed from other caterpillar machines, was its rhomboidal shape and all round track which were the invention of Lt. (later Lt.-Col.) W. G. Wilson, working in conjunction with Mr. (later Sir) W. Tritton. This machine, afterwards known as the Mark I. tank, was tk prototype of all British machines used during the World War.

In the meantime normal trench warfare had been proceeding in France. The artillery had been considerably strengthened, but even then it was found at the battle of Loos that large numbers of enemy machine-guns would survive the heaviest bombardment and cause prohibitive casualties to the attacking infantry. G.H.Q. France therefore ordered 40t! of these experimental tanks, and this number was increased by the War Office to 100 machines. A tank supply committee was formed under the Ministry of Munitions with Major (later Sir) Albert Stern as chairman. Orders were placed on Feb. 12 and production started at once with utmost secrecy, and under great difficulties of labour and material owing to the great national effort to produce munitions of every kind.

The First British Tanks.—The Mark I. tank was built in two types, “ male ” and “ female ”; both types had “ sponsons ” mounted on the sides to carry the main armament. On the male tank this consisted of two 6-pdr. guns and on the female tank of four Vickers machine-guns. The idea was that the tanks would work in pairs, the male tank being more capable of dealing with defences behind brick walls or steel loophole plates and the female tank having greater man-killing fire power. The total number under construction was 150, half being males and half females. The Mark I. tank was 26 ft. long, weighed 28 tons and carried a crew of eight men. The maximum speed on the level was 4 m.p.h. and the tank could cross a trench 10 ft. wide. Reference has already been made to the track which was carried all round the tank; this track was driven from the engine through a two-speed gear box (controlled by the driver) and then through a differential which carried a second gear box at each outer end of the half shafts. These secondary gears were operated by hand levers and necessitated a gearsman on each side of the tank in addition to the driver. From these the drive was carried by chain to the driving sprockets in rear. As the original idea of the inventors had been that the tank should be used as a surprise on a large front the armour was for most part only proof against ordinary rifle ammunition. It was realised that it might be necessary, as was indeed the case, to increase the thickness of the armour, in later models, to withstand armour-piercing bullets, when the enemy had had time to produce large quantities of these bullets. The male tank carried 324 rounds of 6-pdr. shell and 6,272 rounds of S.A.A. The female tank carried 31,232 rounds of S.A.A. Both types carried sufficient petrol for about 15 m. on a cross-country course.

A feature of this tank was the tail which consisted of a pair of steel wheels hinged on to the back of the machine and pressed down on to the ground with powerful springs. The wheels could be steered from the driver’s seat and in this way the tank could negotiate easy bends; the wheels improved the balance of the machine and also slightly increased the trench crossing capacity. In order to take a sharp bend or swing round on its own axis, the wheels were raised by a small hydraulic ram and secondary gears placed in neutral on one side of the tank. The power of the engine was then transmitted to one side only and the tank would take a sharp bend, or if a brake was applied on the same side as the gears were in neutral, then the tank would swing on its own axis. In March 1916 a unit was formed to man these first tanks. For the purpose of secrecy the unit formed part of the Machine Gun Corps and was known as the Heavy Section, Machine Gun Corps. This name was later changed to Heavy Branch, Machine Gun Corps. The unit was commanded by Col. Swinton and contained sufficient personnel to man the 150 tanks under construction. The unit was organised in six companies of 25 tanks each. As soon as the tanks began to arrive from the contractors the unit encamped at a secret area near Elvedon in Suffolk and started driving and gunnery practice.

Il. THE TANK IN ACTION First Engagement on the Somme.—In the meantime the Somme offensive in France had come to a standstill. The right wing of the attack between the Somme and the Ancre which had met with some success at the start was definitely held up. The very heavy bombardments of the greatly increased artillery force had enabled the attackers to make some headway, but in the end the artillery fire had shelled away the barbed wire and replaced it by a worse obstacle, namely shell torn ground over which the infantry could only advance with difficulty, especially in wet weather. Moreover, this ground was quite impassable to transport and any question of pressing forward at some point where an attack had met with success was rendered impossible, as no ammunition or supplies could be sent up until new roads had been constructed. It was at this stage that it was decided to use the first two companies of tanks in an attempt to resuscitate the advance between the Somme and the Ancre. These two companies were accordingly sent to France at the end of August.

On Sept. 15 1916 the first tank attack took place. The IV. Army was to attack and advance on the line Morval, Les Boeufs, Guendecourt and Flers and the V. Army on the left of the IV. Army was to advance on Martinpuich and Courcelette. A total of 49 tanks were to be used, the majority with the IV. Army. They were to advance in small detachments of two or three machines against the enemy strong points. The general idea was that they should advance so as to reach the objectives just before the infantry. In some cases lanes were left in the artillery barrage up which the tanks were to advance ahead of the infantry. The tanks advanced at dawn in a slight mist and came as a complete surprise to the enemy; the results were, however, disappointing. The tanks had been constructed to traverse wide trenches, banks and barbed wire obstacles, but not the shell torn ground which was the result of prolonged bombardment on a small area. Of the 49 tanks which were employed, 32 reached the front line. Of these nine went ahead of the infantry and rendered valuable assistance; nine kept up or followed, just behind and helped in reducing strong points where the enemy were still holding out. The remaining 14 broke down or sank and became ditched in the soft shell torn ground shortly after the battle had commenced. One tank in front of Flers gave remarkable assistance to the infantry and caused the surrender of 300 Germans. On Sept. 25 and 26, 13 tanks were employed on the same front and a few were employed later, on Nov. 13. In each case a large proportion of the tanks were unable to negotiate the shell torn ground, but those that did rendered valuable assistance to the infantry, causing heavy casualties and the surrender of a large number of Germans.

The employment of the tanks in Sept. 1916 was conte to the views of those who had originated the arm and were responsible for its production. They considered that the tanks should be kept as a secret and used in large numbers as a surprise on a new portion of the front so as to give a chance of achieving decisive success. By using the tanks in small numbers a repetition was created of the error made by the Germans when they released gas on a small scale on April 22 1915. It was done in order to resuscitate the Somme offensive and raise the morale of the troops, but it is doubtful if the value so gained was equal to the loss of surprise in the use of a new weapon which it entailed, It did however prove that the tank was a very definite reply to the machine-gun and barbed wire and that infantry accompanied by tanks could attack defended positions with every prospect of success.

Improved Types.—As a result of these trials it was decided that the arm should be expanded to a force of 1,000 tanks. The tanks were not to be used again until the spring and the winter was to be spent in re-arming and training. The original six companies were expanded to nine battalions and the force in France was to become three brigades, of three battalions each, under the command of Lt.-Col. (afterwards Major-Gen.) H. J. Elles, R.E. Each battalion was organised in three companies and one mobile workshop, and each company was composed of four sections of four tanks each.

Although France had asked for 1,000 tanks, the design of the tanks had not been settled. There was much discussion as to whether a completely new design should not be introduced; suggestions were made that a type with much wider tracks, or possibly equipped with more than one pair of tracks, should be tried. In the meantime roo machines were ordered which were to be similar to the Mark I. machine, but with certain minor improvements. These were known as the Mark II. and Mark III. machines. Other than the obvious fact that tanks had difficulty in crossing the pulverised ground on the Somme which was covered with craters and shell holes, the only military lesson that had been learnt as regards tank construction was the fact that it was not worth while fitting the tail to the tank; owing to its vulnerability and complications, it was constantly out of action and was of little value. The Mark IF. and III. machines were therefore both very similar to the Mark I., the main differences being the provision of stronger rollers, and stronger armour to withstand the armour-piercing bullets which the Germans would be fairly certain to use in the next battle.

In the meantime the authorities in England who were responsible for the production of tanks were becoming perturbed about the delay over a decision as to the design of tanks for the order of 1,000 machines. For the original idea of fighting a surprise battle on a new front the existing design was suitable, but to produce the ideal machine for traversing the shell torn ground of an old battlefield, a new and special design was necessary and this would mean a complete new series of experimental trials, involving much delay. It was not till the end of March, involving the loss of five valuable months, that a decision was reached and it was then decided that the 1,000 machines should be of a type known as the Mark IV. This type was again very similar to the Mark T., using the same engine and transmission and the same shape of hull. It included the minor improvements already incorporated in Marks II. and III. and in addition had sponsons which could swing into the body for travelling on a railway, and so saved the labour of detaching and remounting these heavy-sponsons for every railway journey. Another feature of this tank was that it carried an unditching beam which could be fastened when required on to the tracks to extricate the tank from, a ditch. The Mark IV. tank was the main machine used throughout 1917 and the early part of 1918.

The next action in which the tanks took part was the battle of Arras on April 9 in which the I., III. and V. Armies attacked with a view to penetrating the German defences and allowing an Army Corps and two cavalry divisions to break through. Only 60 tanks were available for this attack and they were again used in the minor role of assisting the infantry to “ mop up ” machine-gun nests and small posts that had been passed over by the artillery barrage and the assault of our leading troops. The tanks were of the Mark I., II. and III. pattern and some of them suffered heavily from armour-piercing bullets. In many cases the tanks rendered valuable assistance, overcoming enemy machine-guns and barbed wire with ease. Although there had bzen a heavy preliminary bombardment the ground was not torn up to the condition in which it had been on the Somme and the result was that comparatively few tanks became ditched and most of these were soon extricated. The cavalry were prevented from breaking through owing to the usual obstacles—barbed wire and machine-guns—the tanks being far too few in numbers and too dispersed to be able to keep up the pressure and assist in further operations. The lessons were the same as before, namely that tanks should not be dispersed, but used in large numbers and further that succeeding waves were necessary to keep up the pressure and achieve decisive results. Messines.—The next attack was against the Messines-Wytschaete Ridge on June 7 in which 76 Mark IV. and 12 supply tanks were used. The latter were made from old converted. Mark I. or II. tanks and were used to keep the fighting tanks supplied with petrol and ammunition—a need which had been much felt in former battles. The attack was in the nature of an assault in the old form of siege warfare. The result was a complete success in which the tanks only played a small part, though in a few individual cases they rendered valuable help. The ground was completely pulverised by the preliminary bombardment but very few tanks became ditched, mainly owing to the fact that there had been no rain for many weeks and that there had been time to make a close reconnaissance of the ground and pick out the best lines of advance for the tanks. After this attack the arm was renamed as the Tank Corps.

Failure at Ypres—On July 31 the third battle of Ypres was launched. As the preliminary bombardment had been so successful at Messines it was decided again to use a long preliminary bombardment lasting 10 days. The danger of thus rendering the ground impassable to tanks, especially if it rained, was explained by those responsible for the action of tanks, but it was considered that the value of the bombardment more than balanced the possible loss of the use of tanks; this did not prove to be the case as the Germans adopted a defence distributed in depth which did much to discount the value of the bombardment. Unfortunately it rained on the first day of the battle and although the tanks rendered much assistance in individual cases during the early stages of the attack, the ground soon became quite impassable to tanks, and later it became impassable to infantry as well.

Success at Cambrai-—Although the failure of the tanks at the third battle of Ypres was through no fault of the officers and men and those who commanded them, it led to much discussion as to whether tanks should be retained at all. The Germans formed the opinion that the tank was practically useless, and many British officers held the same view. Fortunately this view was not unanimous and on Noy. 20 permission was obtained to launch an attack at Cambrai, in which the tanks were to be used in the way in which their originators had intended that they should be used. This was the turning point in the history of the Tank Corps. 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, seven months before the first tank action. The attack was to be a complete surprise and no preliminary bombardment was to be used. Three brigades of tanks (nine battalions) were to take part with a total of 378 Mark IV. tanks and 98 administrative machines (see CAMBRAI).

The attack was launched at 6:20 A.M. in a slight fog, Maj.- Gen. Elles leading the attack in a vanguard tank with the centre division. The operation was a complete success; the enemy were taken absolutely by surprise and most of the infantry bolted or surrendered. Within 12 hrs. the infantry had advanced 12,000 yd. on a front of 13,000 with only 4,000 casualties. A similar penetration at Ypres had taken three months, with enormous loss of life and morale. The preliminary bombardment which had cost some {22,000,000 at Ypres was dispensed with and a further advantage was gained in that the roads had not been torn up with shell fire and were available for use almost at once. And this had been achieved by the Tank Corps using great mechanical power, but numbering only 4,000 of all ranks. As regards tank design three main lessons were learnt from the battle of Cambrai. First of all the tanks required to be handier, and controlled by one man, without the assistance of any gearsmen, and to meet this requirement the Mark V. tank was produced. This design had been suggested but not accepted almost a year previously. Outwardly the tank had the same appearance as Marks I. to IV., but the engine and transmission were much improved. The engine developed more power and the steering was effected by using epicyclic gears on the transmission to each track; this was the best tank produced during the War. Then the difficulty of crossing the wide trenches of the Hindenburg line had been considerable, and a certain number of special long tanks were ordered for this purpose. These were made from Mark V. tanks by adding a section in the centre to obtain the required length, and were known as Mark V.* tanks. Later an improved type was made with a more powerful engine known as the Mark V.** The third lesson was the necessity at times for a much more mobile tank for use beyond the main trench systems. These tanks would not need to cross wide trenches and hence they could be shorter and lighter and more mobile. One type, known as the whippet, had already been constructed experimentally. These lighter tanks became known as “medium ” tanks, and the whippet was named the Medium Mark A.

German Offensive of March 1918.—The Tank Corps was now expanded to five brigades of 13 battalions with 320 Mark IV. machines and 50 Medium A. machines. During the winter of 1917-8 all units were training and being equipped with new tanks. No further offensive operations were in view and there ensued a period of preparation for the expected German attack in the spring of 1918. To assist in repelling such an attack the Tank Corps was distributed in detachments on a front of some 60 miles.

The attack was launched on March 21 and the Germans advanced rapidly. The tanks took part in many improvised attacks in attempting to stem the German advance. Some of these met with fair success and caused heavy casualties but the tanks were too few and too dispersed to make their real weight felt. It was during this retreat that the Mediuin A. tanks were first engaged in action and they met with considerable success, their additional mobility being of great assistance in this type of warfare. The attack fought itself to a standstill within a month, immobility being caused more by the difficulties of transport than by the resistance offered by the Allies. The supply of ammunition and food to the advanced German troops, especially where the lines of supply crossed the old battlefields, became exceedingly difficult, and it was at this stage that the necessity for some form of cross-country transport to enable an army to pursue across the devastated country left behind by the opposing force, began to be realised. The Tank Corps had already foreseen its own requirements by the provision of supply tanks and sledges drawn by tanks, and later by moving signalling equipment in special signal tanks. A small number of gun carrier tanks had also been constructed at an earlier date for the transport of the heavier guns and ammunition, though these had not been found very satisfactory mechanically. At a later date large numbers of tractors were ordered for every type of transport work, with the idea that at any rate a portion of the army could be made mobile and independent of made roads for its line of supply, but none of these were received before the date of the armistice.

In the meantime a reaction had set in as regards the estimated value of fighting tanks. The critics asserted that the battle of Cambrai could never be repeated and pointed to the lack of decisive results achieved by the tanks during the German advance. The proposed expansion of the Tank Corps was postponed and the existence of the corps seriously threatened. Fortunately the Mark V. tanks were now arriving at the rate of about 60 machines per week, and on July 4 one brigade of tanks equipped with these machines carried out a surprise attack on the Germans at Hamel in conjunction with the Australians. The attack was a complete success. The extra handiness and mobility of this machine enabled it to be used very effectively against machine-guns, many of which were crushed and rolled into the ground.

The Triumph of the Tank.—The great French victory of Soissons on July 18 1918 marked the turning point of the War; the victory was largely due to the use of French tanks employed in much the same way as the British had used their tanks at Cambrai. This was followed by the opening of the British strategic offensive on Aug. 8 with the battle of Amiens. In this attack the tank tactics were those of Cambrai modified by recent experience and adapted to the improved machines available. The attack was carried out by three army corps, a cavalry corps and ii(?) tank battalions; nine battalions were equipped with Mark V. tanks and the remainder with Medium A. tanks. For the first time since tanks had been used for an offensive it was possible to keep some in reserve and 42 tanks were kept in hand. The attack was a complete success, the greatest penetration of the tanks being 73 miles. The tanks continued in action till Aug. II.

From that date until the Armistice tanks took part in every main attack and in no case, where tanks were properly employed in conjunction with the other arms, did the attack fail. During this period the tanks co-operated in the battles of Bapaume, Epehy, Cambrai, St. Quentin, the Selle and Mauberge. Tanks came to be looked upon as essential to the success of any attack, and in his final dispatch the commander-in-chief stated that the successful attacks which won great victories at Amiens and afterwards would have been impossible without tanks. The Germans also confessed that it was the tanks that had caused the downfall of their armies in the feld. An expansion of the Tank Corps to 34 battalions had been sanctioned if the War continued into 1919, and the Ministry of Munitions in England had hoped to produce a total of 6,000 machines in 1919.

Ill. FRENCH AND AMERICAN TANKS Independent Invention by the French.—The French were faced with the same difficulty as the British in the early stages of the War, and their attacks were held up by machine-guns and barbed wire although they were often well supported by artillery using high-explosive shells. It was Col. (later Gen.) J. B. E. Estienne of the artillery who first perceived the necessity for some mechanical machine which could cross the trenches and barbed wire in the face of machine-gun fire, and when this officer saw the Holt caterpillar tractors at work behind the British front for hauling guns, it occurred to him that the solution might be found in an armoured caterpillar machine. On Dec. 1 1915 Col. Estienne put forward his idea officially to the French commander-inchief and asked for an interview. Thus the ideas which had been thought out by the British originators in 1914 were reinvented separately and independently by the French in 1915. As the result of Col. Estienne’s interview, 400 tanks were asked for and the design was to be prepared jointly between Col. Estienne and M. Brille of the Schneider Works. Later a further order for another 400 machines was placed with the St. Chamond Works.

In June 1916 French Headquarters received information from British G.H.Q. as to what was being done in England. Col. Estienne visited England and saw the Mark I. tanks in training. He expressed the view that the two countries should collaborate as regards the production of tanks and that as the British had progressed with the design of a large heavy machine, the French might specialise with a light machine for more mobile warfare. Colonel Estienne was specially insistent in the view that neither country should forestall the other in the use of tanks, but that they should co-operate and launch a great offensive in which both British and French tanks might obtain full value from surprise.

French Light and Medium Tanks.—The first light tank was produced by the Renault firm in Nov. but the production of these small machines did not receive official support. The French classified their tanks or “ chars d'assaut,” as they were called, in three categories, and this classification was generally accepted. The light tanks were under to tons in weight and were to be transported over long distances in lorries. The medium tanks (St. Chamond and Schneider) weighed between to and 30 tons and could be transported by rail on ordinary trucks. The heavy tanks, of which the British Mark I. formed the only example at the time, were machines weighing over 30 tons and required special railway trucks for transport.

A training centre was now formed at Marly-le-Roi and later an additional centre was started at Champlieu. On Sept. 30, the artillerie d’assaut, which was the counterpart to the British Tank Corps, was formed under the command of Colonel Estienne. The French medium tanks now began to arrive. The Schneider tank was six metres in length and driven by a 60 H.P. engine. It was armed with a short 75 mm. gun and two machineguns. The St. Chamond tank was somewhat larger and heavier, being 8 metres in length and driven by an 80 H.P. engine through a petrol-electric transmission. The armament was one 75 mm. gun and four machine-guns. Both machines differed radically from the British tank in that the track was not carried round the machine but consisted of the ordinary short type used on tractors. This resulted in the machines having very limited climbing power out of shell holes or craters. The artillerie d’assaut was organised in “ groupes ”; each “groupe ” had four batteries of four tanks cach. The light Renault tank was used as a “ command ” tank and one was allotted to each “ groupe.”

The delivery of both types of tank was very slow and instead of 800 tanks being ready for the spring offensive in 1917 only 250 had been received. The result was that only 10 “ groupes ” were able to take part in Gen. Nivelle’s offensive. The French high command. had grave doubts whether to make use of so small a number of tanks, but eventually decided to do so. The offensive was unsuccessful and although the tanks did good work in isolated cases, the result was disappointing. The employment of tanks in this manner was a repetition of the mistakes made by the British. The attack was not launched as a surprise and the tanks were dispersed and used in small detachments. The tanks showed certain faults but mainly mechanical troubles that were already known. The main fault was lack of climbing power owing to the body projecting beyond the front end of the tracks.

Success of the Renault Type—Between this date and the end of the year 1917, the French tanks were again used on several occasions with similar results. On Oct. 23, five “ groupes ” took part in the battle of La Malmaison and met with much success though the battle was not launched as a surprise and was preceded by an artillery bombardment. During this period much discussion took place and designs were prepared for improved medium tanks and for heavy tanks. Finally in Dec. 1917 it was decided to concentrate on the Renault light type; this was the machine that Col. Estienne had asked for in 1916. Some of these tanks were already on order but production had been very slow. In Jan. 1918 it was decided to increase the orders to a total of 4,000 light tanks, of which 1,000 were to be ready by the end of March. The Renault tank was a small machine weighing 63 tons. The length was four metres and in addition there was a short skid tail in rear to assist in trench crossing. It was driven by a 35 H.P. engine. ‘There were two types, one being armed with a 37 mm. gun and the other with one machine-gun. The crew consisted only of two men, one driver and one gunner.

The French had hoped to use their tanks in mass in a great offensive in the spring or summer of 1918, but the German advance on March 21 upset all these plans. Instead the tanks were used piecemeal and in local counter-attacks to stem the German advance. In May and June tanks were used on occasions and the Renault tank made its first appearance in battle on the east of the Forest of Retz. During this time the Artillerie d'assaut was reorganising and rearming. On July 18, the battle of Soissons took place and the French tanks came into their own. It was in many ways a repetition of the battle of Cambrai but as the warfare had been of a semi-mobile nature for some months, the wide trenches of static warfare were non-existent. This suited the Renault tanks. The attack was launched as a surprise using a total of 120 medium tanks and 700 Renault tanks. The attack was a complete success and definitely established the value of the tank in the French Army. From that date until the Armistice, the French tanks—mainly Renault tanks—took part in practically every attack and contributed largely to the success of the final French offensive.

American Tanks.—The Americans were quick to grasp the great possibilities of tank action on the Western Front and this form of mechanical warfare appealed to their national characteristics. Officers were sent to study the employment of tanks and questions relating to their construction and design. As a result the Americans decided to adopt the British heavy type of tank and the French light type known as the Renault tank. In Dec. 1917 an allied commission was formed and it was decided to construct a tank known as the Allied tank; this was a heavy tank similar to the latest British type and was to be the Mark VIII. tank for the British Army. It was designed to use the Liberty aero engine and was known in America as the Liberty tank. A factory was erected at Neuvy Pailleux which was eventually to be capable of constructing and assembling these tanks at the rate of 1,200 a month and the first 600 were to be used for equipping the first American tank units. A large constructional programme was also started in America to produce both this type and the French Renault tank. The first tanks of this type were not constructed until just after the end of the War, but several American tank units equipped with British and French tanks took part in the latter phases of the War and met with marked success. If the War had continued the American tanks would have come in with an overwhelming effect in 1919.

Anti-Tank Defence.—The Germans never made any attempt to construct tanks in large numbers, partly due to the restricted manufacturing power possessed by Germany compared with the Allies, and partly due to the comparative failure of the British tanks at Ypres in 1917. A rather clumsy type of heavy tank known as the A.Y.V. was constructed in small numbers. These and a number of captured machines were formed into units and used in small numbers in a few isolated cases during 1918, but owing to the way in which they were employed and handled they met with little success.

On the other hand the Germans made continual attempts to introduce some form of anti-tank defence, but as the British tanks met with comparatively small success in the early stages, these measures were only developed half-heartedly. The first step was the introduction of armour-piercing bullets which was countered by the use of thicker armour on the Mark IV. tank. Next the Germans turned their attention to the employment of field guns specially allocated for anti-tank defence and often dug in or concealed in the forward areas. ‘The employment of field guns in this way seriously depleted the power of the German artillery for other purposes, but they were meeting with considerable success until the introduction of the Mark V. tank, which, with its increasing mobility was able to reduce very largely the value of this field gun defence.

In addition the Germans often employed obstacles such as pits and barricades or mines. The former required a large amount of material and labour in construction, and could usually only be made in isolated places or in defiles, and did not seriously trouble the allied tanks. The latter were a source of danger to friend and foe, and required much time and material before a continuous line of minefield could be constructed. Although tanks were blown up in isolated cases by German mines the danger was never serious. The Allies made preparations to meet enemy tank attacks with field gun fire and in some cases by the use of male tanks kept in hand for this purpose. The latter is the most certain method of secure defence against tanks but was never adopted by the Germans. In 1918 the Germans evolved a heavy anti-tank rifle which was capable of penetrating the armour plates of the tanks, but the rifle had a heavy recoil and was difficult to handle and did not prove successful as an anti-tank measure.

After the success of the Allies at the battles of Soissons and Amiens in July and Aug. 1918 the Germans were awakened to the great danger in which they stood from tank attacks. They then constructed a heavy machine-gun firing a 13 mm. bullet and capable of penetrating 30 mm. of armour. The gun was known as the Tuf, and great efforts were made to construct it rapidly and secretly, but none were ready till after the Armistice. The Allies knew of the construction of these guns and realised the value which they would possess for frontal defence. They hoped however that the increased mobility of at any rate a proportion of the tanks in 1919 would enable them to penetrate and attack the enemy in the rear or along his communication and thus discount to a large degree the increased defensive power of the Germans against a frontal attack by tanks.

IV. PROGRESS SINCE THE WORLD WAR Since the War progress has followed similar lines. Some nations have adopted a special anti-tank gun and others a heavy machine-gun but the most secure method is still the employment of some form of gun on a vehicle which can travel cross-country, and this in effect becomes a tank, though it may be a tank specially designed as a tank destroyer.

Experimental Patterns.—With the exception of the Germans, who are prohibited by the Peace Treaty from doing so, all great nations now employ tanks as part of their military force. The French have retained the Renault tank as the main armament of their tank corps and although they have carried out much experimental work with heavier tanks, no models have been considered sufficiently advanced to standardise and construct in any large numbers. The Americans have also constructed many experimental patterns but have retained the Mark VIII. or Allied tank as the heavy tank with which their tank units are equipped and the Renault as the light tank.

The British, as the originators of the tank, have made great efforts to maintain their lead. Some months before the conclusion of the World War, when preparations were being considered for a great offensive in 1919, the specification was drawn up for a tank which was to be a great advance on the existing patterns. It was to have a speed of 20 m.p.h. and be capable of floating and propelling itself across water. Enough petrol was to be carried to travel 200 m. cross country and the tank was to be long enough to cross a trench 12 ft. wide. This tank was to be used for attacking the enemy communications and headquarters while the more conventional tanks were attacking the main armies in front. The first experimental model was actually completed just after the Armistice. The tank used a system of spring suspension on a cable and hydraulic power for control. Although the machine attained a speed of 28 m.p.h. and swam successfully across a narrow river on several occasions, it proved to be unreliable owing to the many new devices which it contained and which required further development. The next step that was tried was to produce a machine with an improved form of steering. Up till then tanks had been steered by locking one track and skidding round to the desired direction. This method of steering absorbs a large amount of power and brings large and unnecessary strains on the track and transmission. The device now tried was to produce a track with lateral flexibility so that it could be laid in a curve and enable a tank to take ordinary curves in the same way as any other vehicle. The problem however was found to present many mechanical difficulties and, although much work has been done, no satisfactory solution has yet been found as far as tank construction is concerned.

The Vickers Light Tank.—In the meantime the British Tank Corps which was reduced to four battalions after the War, was armed with the Mark V. tank and the Medium C. The Medium B. replaced the Medium A. at the end of the War, but very few of this model were made and the units were equipped with an improved type in the Medium C. This machine had a maximum speed of 12 m.p.h. and a radius of action of 70 m. and would have been a very useful tank in France. But by 1920-1 these machines were becoming worn out, and, although much knowledge had been gained, the experimental machines aiming at far higher achievements, and which have already been referred to, were not yet in a satisfactory state for production. A tank was therefore designed which was constructed on conventional lines and aimed at obtaining a high degree of mobility, if necessary at the expense of trench spanning capacity. The machine was known as the Vickers light tank. It is 18 ft. in length and weighs 10 tons and is armed with one 3 pdr. gun and two machine-guns. It can attain a speed of 20 m.p.h. and travel 150 m. on the petrol that it carries. Owing to its short length the tank has poor obstacle-crossing capacity, but in other respects it has proved very satisfactory.

The Future of the Tank.—Since the War there has been much discussion on the subject of mechanical warfare, initiated mainly by books and essays written by Col. J. F. C. Fuller who acted as General Staff Officer to the Tank Corps in France. The great saving in man power that can be effected by using mechanical power instead of men and horses for transport purposes is now fully realised. Reference has already been made to the necessity of using tractors to render an army capable of cross country movement independently of roads and much has already been done in mechanicalising the transport of artillery in the British service. A detailed consideration of this subject is, however, beyond the scope of an article on tanks. More recently attempts have been made to produce a force composed of infantry, tanks and artillery, the whole force being capable of moving 100 m. in 24 hours by means of mechanical power. Such a force would have a value in war far beyond its numerical strength in men. Preliminary trials of this nature have already been carried out on manoeuvres in England but the whole subject is at present in its infancy.

More recently experiments have been carried out in England with very small tanks with a crew of either one or two men only. The one man tank is constructed from the type of engine and transmission in normal commercial use and the tank is therefore both cheap and easy to obtain in large numbers for war. ‘The control is so arranged that one man can fire the machine-gun at the same time that he is driving the tank. Tactically the object of employing such small tanks is twofold. In the first place they are required for scouting and reconnaissance duties. A commander who uses ordinary tanks for such purposes risks losing his tanks on minor enterprises before the main battle takes place; on the other hand infantry are slow in performing these duties and cavalry are often too vulnerable. The small cheap tank possesses none of these disadvantages. The second object is to obtain increased safety against anti-tank fire by the use of dispersion. As many as 20 of these small machines can be provided for the cost of one large tank, and by the use of large numbers it should be possible to advance in the face of anti-tank fire where a small number of large machines would fall an easy prey. These small tanks are capable of traversing any ordinary country at an average speed of 10 m.p.h. and can cross a trench about 4 ft. 6 in. wide. If warfare continues to be a serious possibility between great nations in the future, the development of great tank armies is certain. Heavily armoured tanks carrying large calibre guns will be the main arm in the battle, and these will be assisted by larger numbers of small tanks for reconnaissance and protective purposes. In addition there will be the administrative tanks or tractors for communications, engineer work and supply purposes.