The rational use of coast-artillery, and the development of a correct system of defence, are based upon a knowledge of the means of defence, of the capability of those means, and of the method of employing them.
It is almost universally conceded that to-day, as in the past, fortifications play the most important rule in the. defense of coasts and harbors. In the United States, submarine mines and other obstructions are officially regarded as auxiliaries...