The development of speed has therefore a special interest. Between 1859 and 1875, that tentative period which led to such wonderful realizations, the highest speed, under the most favorable circumstances, of large war-vessels was fourteen knots; in the smaller classes of unarmored ships it ranged between eight and thirteen, while that attained by fast cruisers was from fifteen to sixteen and a half knots. In 1886 Italian armored vessels made eighteen knots. Cruisers like the Japanese _Naniwa-Kan_ and the Italian _Angelo Emo_ reached nearly nineteen, and the _Reina Regente_, launched in February last, is expected to steam over twenty. Torpedo-vessels beginning in 1873 with fourteen knots are now running twenty-five, and at the same time the type has so much increased in size and importance as to be an essential and not an accessory in naval warfare. It is impossible to explain the difficulties which have beset this development, because the conditions that surround any attempt at speed-increase are such as can be properly understood only by those who have technical training; and then, too, the great ocean racers have so much accustomed the public to wonderful sea performances that the results are accepted without a knowledge of the credit which is due the mechanical and marine engineers who have achieved them. But with greater experience the higher, surely, will be the appreciation which every one must give; for, in the words of Chief Constructor White, “when it is realized that a vessel weighing ten thousand tons can be propelled over a distance of nine knots in an hour by the combustion of less than one ton of coal—the ten-thousandth part of her own weight—it will be admitted that the result is marvellous,” and that “‘the way of a ship in the midst of the sea’ is beyond full comprehension.”