tions, and for submarine explosions. The recoil of the gun is much less with a charge of gun cotton than with one of gunpowder, giving to the projectile the same initial velocity. This admits of the use of much lighter field guns with gun cotton for the propelling charge, as is the case in the Austrian service, and gives them a superior mobility, affording great advantages, particularly over soft and difficult roads or fields of battle. In view of the great advantages for some special military purposes which the improved gun cotton of Baron General Lenk is known to possess, it is recommended that the privilege of making it after his patented process be obtained, with full information as to all the details of the process of manufacture. The principal European nations have already adopted this course, and the British Government is now experimenting on the gun cotton made at the Waltham Abbey Powder Works. Although the improved process of General Lenk has accomplished important results, it is believed that much remains yet to be done to modify the action of gun cotton so as to adapt it still better to military purposes, and, like many other new ideas and processes of manufacture which have been introduced into our military service, there is little doubt that it may soon be so improved as to overcome the objections to its more general, if not universal, use.

A most essential want of the military service, and one which has been most seriously felt, is that of a suitable ground for the proof and experimental firing of ordnance and small-arms. New inventions and improvements in these are constantly brought to the notice of the department, the practical value of which can only be ascertained by experiment. Some of these inventions or improvements are seen by examination to possess the advantages claimed for them, while grave doubts arise as to whether these advantages are not more than counterbalanced by defects growing out of the very devices relieved on by the inventors for attaining advantages. Others are altogether theoretical, and require the test of actual trail to verify or refute their supposed merits. These inventions and improvements should not be disregarded, as they may result in important benefits to the public service. It will not do to stand still and rest content with what we have already attained. We must entertain and prove plans and devices for improving munitions of war if we are to keep pace in these with other nations, and in order to do so we must have the means of proving them. We must entertain and prove plans and devices for improving munitions of war if we are to keep pace in these with other nations, and in order to do so we must have the means of proving them. We are now without the proper means of so doing, and it is suggested and earnestly advised that a proper proving and experimental ground be selected and acquired. The selection should be made by a board of officers of professional acquirements and experience; and authority should be given to the Secretary of War to purchase a sufficient quantity of the ground so selected to serve for the purpose of proof and experiment with ordnance, small-arms, and other munitions of war.

The heavy gun of 20-inch caliber, for sea-coast fortifications, has been successfully cast and finished, and a suitable carriage to mount it has been prepared. It is now ready for experimental trials at Fort Hamilton, in New York Harbor, and the proper targets and other preparations for testing its efficiency against the strongest was vessels, and ascertaining the best manner of handling it in service, have bene ordered to be made. The results of these trials will demonstrate whether the expectations which theory warrants, of the destructive effects of this gun and its value for defensive works covering narrow passes, are realized, and whether such guns should be multiplied; and if so, to what extent. If they should establish the affirmative of this question, the cost of their trials will be far outweighed by the advan-