genius, and open to the entrance of valuable ideas which would have been utterly excluded by all the old and established rules. But the actual work of the unexampled mental activity of the present day, will not be fully known and estimated until after the close of the war. Until then there will be neither time nor opportunity to weigh and test the creations of the national ingenuity. In the midst of campaigns and battles, with the absorbing interest of the great struggle, the instruments of warfare cannot be easily changed, however important may be the improvement presented. The emergency which arouses genius and brings forth valuable inventions, is by no means favorable to their adoption and general use. On the contrary, by a sort of fatality which seems to be a law of their existence, they are doomed to struggle with adversity and fierce opposition, and they are left by the occasion which gave them birth as its repudiated offspring--a legacy to the future emergency which will cherish and perfect them, make them available, and enjoy the full benefit to be derived from them. The navy has always justly been the pride of our country; and it was to be expected that it would first feel the impulse of inventive genius. Confident in our strength and resources, we had long remained comparatively sluggish, and regardless of those interesting experiments which other great maritime powers had been carefully making with a view to render ships invulnerable. We looked on quietly, observed the results, and waited for the occasion when we should be required to put forth our strength in this direction. When the war commenced, we had not a single iron-clad vessel of any description. It became necessary that the immense Southern coast of our country should be subjected to the strictest blockade. This was a work of vast magnitude, and a very large and sudden increase of the navy was demanded by the extraordinary emergency. Cities were to be taken, and strong fortresses to be attacked. The rebels had managed to save some of the vessels intended to be destroyed at Norfolk, and had converted the Merrimack into a formidable monster, which in due time displayed her destructive powers upon our unfortunate fleet in Hampton Roads, in that ever-memorable contest in which the Monitor first made her timely appearance. The chief result of the vast effort demanded by the perilous situation of our country, was the class of vessels of which the partially successful but ill-fated Monitor was the type. These structures are certainly very far from being perfect as ships of war; nevertheless, they constitute an interesting and valuable experiment, and mark an advance in naval warfare of the very first importance. They establish the form in which defensive armor may perhaps be most effectively disposed for the protection of men on board ships; but at the same time, it must be conceded that they utterly fail in all the other requisites for men-of-war and sea-going vessels.