Capt. F. V. Greene, late of the U. S. engineering corps, appears as the advocate of American fortifications, and at the Massachusetts Reform Club he presented his views substantially as follows: The United States have 3,000 miles of Atlantic and Gulf coast, 2,200 on the lakes, and 1,200 on the Pacific, and have cities on these coasts aggregating a wealth of $6,000,000,000--all exposed to a hostile fleet, which could in a short time destroy everything within cannon-shot from the water, and drive five millions of people from their city homes. The fortification board estimates $120,000,000 as the sum necessary to supply cannon and forts for protection, which is but two per cent upon the amount of property protected. This is a very satisfactory statement of the case from the average standpoint, which is not the ethical. But in the first place I consider it morally sure that this country will never have a foreign war if it models its national policy on the Divine law; and secondly, whenever war is foreseen as probable in consequence of an intolerable spirit of aggression and the refusal of the hostile party to submit to arbitration, a sufficient number of cannon can be cast and placed on floating batteries or behind iron walls to protect every endangered point. It would be necessary only to know that our foundries were adequate to the task; and the fact that such an armament was preparing would be a sufficient warning to avert a hostile movement. Yet the costly steel cannon, which require such enormous appropriations to prepare for their manufacture on a large scale, are not absolutely necessary. It has been shown by recent experiments that dynamite shells of 150 pounds can be thrown two miles and a quarter by air pressure or steam pressure from light, slender-built cannon, or steel tubes of unusual length, which may be enlarged to compete with the most formidable artillery. A single steel-clad vessel of the Monitor type with such an armament could destroy a squadron. But let arbitration be known as our fixed national policy--let us secure also the co-operation of other nations pledged to the arbitration policy, and war would be almost an impossibility. Capt. Greene's exposition of the necessity of coast defence was clear and forcible, but his concluding remarks gave a glimpse of peaceful purposes. "He supplemented his speech by remarking that the United States will probably be called on before long to be the arbitrator between the nations of Europe. The latter cannot stand the financial strain much longer, and inside of twenty years we shall probably be the equal in population and wealth of any two, if not three, nations of Europe, and to us will be referred all their disputes for settlement. When we become the referees of the world we must have the force behind us, so that when we give a decision we shall be able to enforce it; and this can only be adequately effected by a perfect system of coast defences."