The big Skoda mortars owed their mobility to the clever way in which they were constructed. The gun tube itself, the support for it or mounting, and the steel foundation were each fitted to a special motor-driven trolley. The steel foundation was dumped down on the ground, which of course was prepared for it in advance, then the mounting was run right on to it so that it simply needed bolting down and finally the tube was hoisted by specially prepared appliances into its place. It is said that the whole operation occupied less than an hour. For firing, these mortars of course are pointed at a very high angle, almost like an astronomical telescope. No doubt the gunners have many jokes about "shooting the moon" and so on, for that is just what they seem to be attempting. For loading, however, they are lowered into a horizontal position: the shell comes up on a small hand-truck, is raised by a specially designed jack until it is level with the breech, and is then pushed into its place. The breech is then closed, the tube re-elevated, and all is ready for firing. Between these two forms of gun, the field gun on its light carriage, which not only bears it from place to place but forms its support while in action, and the great mortar carried in parts on specially made trolleys, there are now an enormous variety of guns and mortars adapted for the various purposes which experience in the Great War revealed. Artillery suffered many changes in the light of the South African campaign and of the Russo-Japanese war, but of far more importance have been the lessons learnt in Northern France and on the plains of Poland. To some extent these lessons have been learnt and profited by during the actual war, but there is no doubt that as men have time to think over them in the years of peace which are ahead many more developments will take place. Unless, that is, we are on the threshold of that happy time when guns and fighting material of all sorts will be looked upon as the relics of a bad and ruinous time now happily past. In conclusion, a passing reference must be made to the trench mortars and similar contrivances which have arisen as the result of the prolonged spell of trench warfare which no one had ever contemplated. These are in effect very short range mortars or howitzers, specially intended for throwing bombs from trench to trench. Some are simply the larger mortars on a small scale, but one has decidedly original features. This consists of a short light mortar into which the bombs are slipped through the muzzle, thus reverting to the old method of loading. The propellant is combined with the bomb and there is a percussion cap which fires it as soon as it strikes the bottom of the tube. Thus the operation is just about as simple as it can be: the man merely places the bomb in the upturned muzzle and lets it slide down. An instant later, up it comes again, to go sailing through the air into the trench of the enemy a hundred yards away.