For some reason or other the aviation of the enemy has not caused very great damage to our various ammunition stores. The damage, as a rule, has been confined to the explosion of the stacks directly hit, although, at the beginning of the operations on the Somme, a German aviator succeeded in destroying completely in the rear of the English lines a large park of all sorts and sizes of shells. The Allies also have often caused the explosion of German munition depots, but the damage done, to all appearances, has always been limited. =5. Replacing the guns.= We have just seen that some field guns fire as many as 3600 shots in a few days. This, added to the rapidity of the firing (at times fifteen shots a minute, during barrages), explains the rapid wear of the guns, whose metal becomes decomposed by the heat. In spite of the quality of the steel, the guns wear out and finally burst. It is of the utmost importance to replace those put out of service by wear, or by the fire of the enemy. This duty rests with the Divisional Park, which must have a reserve sufficient for all needs. The park must also be prepared to repair all the guns which are not so badly injured as to require shipment back to the Army Park. The battery to whose consumption of munitions we have previously referred had, from the 12th to the 19th of April, to make the following changes: Two guns were put out of service by the fire of the enemy; One gun exploded; Seven guns had to be sent to the parks for repairs to their mechanism or their carriages, which had been put out of service. When the mechanism, the wheels, or a part of the carriage only have been damaged, repair is rapidly made, but when the guns have exploded or have been smashed by the enemy’s fire, they have to be recast. In short, a battery of four guns, used ten guns in seven days; but it should be noted that out of these ten guns only three were entirely put out of service (two of the carriages could be used again) and two of the guns merely needed a change of tubes. Nevertheless, these figures emphasize the need for the parks to keep on hand a large stock of reserve guns and to maintain workshops for the immediate repair of slightly damaged pieces. The retubing of the guns is a work that can only be done in the factories of the army. The interior rifled tube, while white-heated, is removed and replaced by a new tube which is re-rifled. The gun is then as good as new, but, if the outside tube, which is the resisting part of the cannon, has been broken by projectiles, the gun is beyond repairing and has to be sent to the rear to be recast. Under the most severe bombardment the replacement of the guns, thus put out of service, did not take more than two hours.