ON STEAM VESSELS.
The application of steam to the propelling of ves sels on the ocean, is likely to produce as great a revo lution in warfare as the first introduction of cannon; and its general influence on navigation will claim in its ultimate consequences, a rank almost equal with the splendid discovery of the compass. As an instru ment of war, it is destined most likely to change the entire aspect of military operations, and to give to its energies a more fierce and terrible character. In a calm, a ship of war impelled by steam, will possess a decided superiority over an opponent navigated only by sails; and battles that sometimes remain unde cided, on account of the failure of the wind, would by the sure and certain energies of steam, be speedily accomplished. Coasts, rivers and harbours, that, according to the ancient plan, were considered as se cure, will by this new application of vapour, be as sailed and defended by them. The system of war fare will be entirely altered, and perhaps the steam gun will lend its aid in assisting in the work of hu man destruction. A modification of the energies, however, that render it so terrible in war, will assist the milder and more beneficent purposes of com merce, and direct the steps of civilization into re gions now debased by gloom and superstition. Thus it is that art, as well as nature tends to preserve a balance in all its operations. If the application of steam to the purposes of war be likely to increase the sum of human calamity, so will the sum of human happiness be augmented by the impulse it will com municate to the whole social system.
The different modes of propelling vessels on the seas, forms a striking and peculiar picture in the eventful history of man. At first, content from circumstances with the simple application of the lever in the shape of an ore, we find at length the rowers greatly multiplied in number, and their. oars aug mented to enormous lengths, to give to the vessel as great velocity as possible. With the invention of cannon, and the ability of performing more extended voyages, came also the necessity of increasing the di mensions of ships. The additional altitude thus com municated, prevented the advantageous use of oars; and the great uncertainty of the wind made it desira ble to supply its place when its force was insufficient, or when its directive energy operated contrary to that desired, by some other mechanical agent. Hence, by
some it was imagined, that the force of the crew might be advantageously employedby other means than oars; and the communication of motion by means of paddle wheels was one of the earliest of these attempts. By some, also, condensed air was proposed as an agent, and by others the explosive force of gunpowder. The fall of water too was proposed; but all have vanished before the triumphant use of steam.
Among numerous attempts, however, the prize of the Academy of Sciences of Paris in 1753, for the best memoir on the subject, '' Sur la maniere de sup pleer a l'action du vent sur les growls vaisseaux," de serves to be particularly noticed, on account of its exhibiting the remarkable fact, that Bernouilli seemed to have looked to the force of man as the origin of propelling power; so little conception had that very illustrious philosopher, of the splendid application of steam affording the motive power. Bernouilli, to whom the prize of the Academy was awarded, entered into many elaborate investigations respecting the ve locity capable of being communicated to a ship by the force of the crew, and endeavoured to ascertain the mean strength of a man, which he assumed as equiva lent to the power of lifting twenty pounds through three feet in a second for eight hours in a day. The whole of this force not being usually exerted by a man in the action of rowing, he determines the actual part at — of the whole force. then the plane 1000 of resistance at 150 square feet as given by Bouguer, and assuming that the power required to produce a given velocity, is as the cube of that element, while the resistance is as the square. (a supposition not however in accordance with the opinion of many en gineers) he computed the following table: This table will show how limited and confined were the views of that celebrated man, and by what more splendid and magnificent means than he anticipated, motion has been communicated to it vessel. It is a remarkable fact, that in the course of his memoir, Bernouilli mentions his having read the description of a steam engine, hut remarks, that he does not con side• its force, however it may be improved as capa ble of ever being advantageously applied to the pur poses of navigation.