I need not describe the _Holland_ here, but motive power, speed, radius of action, and torpedo are all essentially different; but above all it has been proved that a modern submersible boat like the French _Gustave Zédé_, or _Narval_, or our _Holland_ can remain under water truly “without inconvenience to her crew” for periods of nine or ten hours, so that all the problems connected with submarine navigation may be said to have been solved, except that of seeing under water, for when submerged the submarine is in cimmerian darkness, and more helpless than an ordinary vessel in the densest of fogs. Nor is it likely that invention has said its last word in regard to the submarine now that it is acknowledged to be a weapon of practical value. On this point it is convenient to call to mind the remarkable development of the Whitehead torpedo since it was first adopted in our Navy rather more than thirty years ago. It happens that I have been able to refer to an article on torpedoes which I wrote in _Fraser’s Magazine_ just thirty years ago, in which I described the Whitehead of that day as having a speed of from 7 to 7½ knots, a range of 1,000 yards, and a charge of 67 lbs. of gun-cotton. Now, the speed of our modern Whiteheads is 30 knots, the range 2,000 yards, the charge 200 lbs. of gun-cotton, and, thanks to the gyroscope, it can be discharged with extraordinary accuracy. Admitting, then, that the submarine is with us, and that it will remain, let us see what is likely to be its function in war. The submarine compares naturally with the torpedo destroyer or torpedo boat; like them it will attack by stealth, and it has neither their speed nor radius of action. But, whereas searchlights and quick-firing guns are effective weapons against the latter, they are of little use against the submarine, and as all these craft are to act by surprise, the advantage is strongly in favour of the submarine, which can approach with little danger of being discovered, with the cupola only showing, until close to her enemy, thus rendering a close blockade by large vessels impossible. I have said that is naturally the weapon of the weaker power, but that it can be used and that it will be used by the stronger power acting on the offensive I see no reason to doubt. It can certainly be employed against ships at anchor unless they are suitably protected, and it can probably render good service in removing obstructions and clearing passages defended by torpedoes.