Of later years, American inventors and manufacturers have made great progress in chain-track tractors, but practically all the principles of design were originally applied in Great Britain. The Holt caterpillar is the outstanding American design for tractors which has been adopted during the war.
[Illustration:_The Engineer._] DIAGRAM 6. THE BATTER TRACTOR, 1888.]
[Illustration:_The Engineer._] DIAGRAM 6A. THE BATTER TRACTOR, 1888.]
It is interesting to note with reference to the above inventions that neither Germany nor Austria ever appears to have contributed any basic suggestion relating to track-driven machines.
To return now to the military aspect of our subject, gunpowder did away with armour, for if armour can be pierced its defensive value is lost and it only becomes an encumbrance to the wearer by reducing his mobility and exhausting his muscular energy. Did this change the main problem in the art of war? Not at all, for “the giving of blows without receiving them” remains the unchangeable object of battle irrespective of the change of weapons, and all that happened was, that the soldier, no longer being able to seek protection by body-armour, sought it elsewhere--by manœuvring, by covering fire and entrenchments as typified in the drill of Frederick the Great, the cannonades and sharpshooters’ fire of Napoleon, the fortifications of Vauban, and later on the use of ground by Wellington as cover from fire.
The opening of the war in 1914 saw all sides equipped with similar weapons and in comparatively similar proportions. The great sweep of the Germans through Belgium was followed by the battle of the Marne, a generic term for a series of bloody engagements which raged from Lorraine to Paris. Then came the great reaction--the German retreat to the Aisne, the heights along which had been hastily prepared for defence. The battle swayed whilst vigour lasted and then stabilised as exhaustion intervened. At first cautiously, then rapidly, did the right flank of the German Armies and the left flank of those of the French and British seek to out-manœuvre each other. This led to the race for the coast. Meanwhile came the landing of the British 7th Division at Zeebrugge and then the First Battle of Ypres, which closed the German offensive on the British front for three years and four months.