The first works are at the Falls of St. Mary, on the western extremity of the line. The second works are at Mackinaw. The third works are at the foot of Lake Huron. The fourth works are near Detroit. The fifth works are near Buffalo. The sixth works are at the mouth of the Niagara river. The seventh works are at Oswego. The eighth works are at Sacketts Harbor. The ninth works are below Ogdensburg. The tenth works are at Rouse's Point. The eleventh works are near the head-waters of the Kennebec or the Penobscot. The twelfth works are at Calais, on the St. Croix. All these works are small, and simple in their character, well calculated to assist the operations of armed forces in the field, but incapable of resisting a protracted siege. They are entirely different in their character from those on the coast, the latter being intended principally for the use of our citizen-soldiery, in the defence of our seaport towns, while the former are intended merely as auxiliaries to the operations of more disciplined troops. This system of defence for our Northern frontier has been much commented on by men professing some knowledge of the military art, and various opinions have been advanced respecting its merits. Some have thought that more and larger works should be placed on the western extremity of this line; others attach by far the greatest importance to the central or Montreal portion of the frontier; while others, again, attach a higher value to the eastern extremity of the line.