Only a few heavy-artillery regiments existed before the war. Their armament included few quick-firing 155 mm. Rimailho guns, which, though rapid in action, were too short in range. Other batteries were armed with 120 and 155 mm. siege guns; good types, but too small in calibre, and too slow in action. Moreover all these guns were placed at the disposal of armies which, at the beginning of the conflict, considered them as a reserve stock and kept them too far from the battle-fields of August and September, 1914.
The impossibility of following up the victory of the Marne gradually opened the eyes of the Government to the need of a very large, heavy artillery, but this necessity was frankly admitted only in the autumn of 1915, and then largely under the influence of the example given by our British Allies. They had much more quickly comprehended that no victory would be possible unless supremacy in artillery was achieved, and, with their usual cold determination, had turned all the resources at their disposal to the manufacture of every kind of gun, and mountains of ammunition.
France followed the example.
The progress made enabled us first to hold our own against the German artillery, then to equal it, and finally to surpass it.
Considering the limited means left to France by the invasion, considering the seizure by the enemy of her Lorraine iron deposits, and of her richest coal mines, it must be acknowledged that the effort made from 1915 to 1917 was gigantic.
2. Different sorts of artillery. We shall divide the artillery into three parts: the artillery of an army, of an army corps, and of a division.
Artillery of an Army. This includes heavy artillery of all sizes. The army unit alone possesses guns of greater calibre than 155 mm. The composition of the heavy artillery in an army varies considerably, the number of different types of cannon allotted to any one arm depending upon circumstances and on the work which it is expected to do. According to local needs, therefore, the Generalissimo orders the heavy artillery to be transferred from one army group to another. Similarly, the Chief of a group of armies can, as he sees fit, order such transfers of guns within his command.
We find in the armies howitzers and mortars of the following sizes: 220, 270, 280, 305, 370, 400 mm. (in inches: 8, 10, 11, 12, 14½, and 15¾). Soon we shall have 520 mm. guns (20½ inches). There are also field guns of 120 and 155 mm. short and 155 mm. long (5 and 6 inches) and naval guns of 19, 100, 240, 274, 305, and 340 mm.
The artillery of an army is under the command of a General.
The field batteries of 120–155 mm. are composed of four pieces; howitzer batteries and naval batteries of 100 and 190 mm. are nearly always of two pieces. The largest mortars, and the heaviest naval guns mounted on railroad trucks, operate singly, and each gun is accompanied by several trucks carrying its material and munitions.