The question remains as to whether any antidote to the submarine is likely to be effective. It is possible that one may be discovered, but it is not easy to see in what direction we are to look for it, as the submarine differs from other craft in the fact that the possession of any number of similar vessels, by ourselves for instance, affords little or no protection against a few well-handled _Gustave Zédé’s_ in the hands of our enemies. At the same time they would be of little or no value against torpedo boats or destroyers; and cruisers blockading, moving about at a speed of 10 knots or more, at some distance from a port known to harbour submarines, would have little to fear, as it could only be by a lucky chance that a submarine could approach near enough to them to have a fair shot. It is also worthy of remark that the navigation and pilotage of a submarine, even with her cupola above water, would be by no means easy in shallow water or thick weather, and of the value of the periscope I cannot but feel somewhat sceptical. The French are stated to have found that submarines can be easily discovered from balloons; but this must naturally apply only to daylight and fine weather, and their opportunity will naturally occur in thick weather or at night. I have offered these remarks to show that though I consider the submarine to be an important weapon, it clearly has its limitations, and I suspect that when we have them fairly under trial we shall find that when these are fully appreciated and the position of the submarine in naval warfare is duly assigned, much of the terror and mystery now surrounding this novel weapon will be removed. Probably it will be found to be a more dangerous and effective torpedo boat, and will supplant it in great measure. Mr. Fyfe has done good service in giving us this popular account of submarines, which is a valuable addition to the scanty literature of the subject in the English language. THE PROBABLE FUTURE OF SUBMARINE BOAT CONSTRUCTION. BY SIR EDWARD J. REED, K.C.B., F.R.S., M.P. (_Chief Constructor of the Navy 1863–70._)