Discoveries in the Arts.

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Chap. 9.]

world than it has yet accomplished. It is by it only that the energy ofelastic fluids can be economically employed.

Those ingenious men who first constructed a bellows, a syringe, or apump, little thought that similar implements should become self-acting, andeven be motive engines to drive others. What weary laborer at thepump in ancient Greece or Rome, ever dreamt, while indulging in thosereveries that the mind conjures up to divert attention from toil or pain,that a machine similar to the one upon which his strength was expended,should be devised to work without human aid:—and that a modificationof it, excited by the vapor of a boiling cauldron, should exert a forcecompared with which the power of the Titans was impotence—a forcethat should drive fleets of gallies through a storm—hurl missiles like thebalistffi—propel chariots “ without horses”—polish a mirror—forge ahatchet, a tripod or a vase—and spin thread and weave it into veils, fineas those worn by the vestal virgins—and yet should never tireJ Couldthe imaginations of the depressed plebeians and slaves of antiquity havehad a glimpse of such a machine, and had they been informed that itwould in some future time, which the oracles had not revealed, be gene-rally employed—how vehemently would they have importuned the godsto send it in their days ! And why did they not have it ? Because theuseful arts were neglected and their professors despised—while thoseprofessions the most destructive of human felicity were cultivated. Warwas accounted honorable, and hence nations were incessantly engaged inconflicts with each other—a military spirit pervaded the minds of thepeople, and it rewarded them by soaking every land with their blood.

The history of machines composed of pistons and cylinders also illus-trates the process by which some simple inventions have become appliedto purposes, foreign to those for which they were originally designed—each application opening the way for a different one. In this manner de-vices apparently insignificant have eventually become of the utmost value,and it is probable that there is no mechanical combination or device, how-ever useless it may now appear, but which will be thus brought into play.These machines also teaeh us how new discoveries are made in the arts,viz : by observing common remlts, and applying the principles or processesby which they are induced, to other objects or designs. Every mechani-cal movement and manufacture—an unsuccessful experiment—defects orderangements of ordinary machines, &c. are all practical demonstrationsthat indicate the means to produce analogous effects, or to avoid them.Fulton employed steam-engines to turn paddle wheels—Eli Whitney adopted circular saws as cotton gins; and both became benefactors oftheir country—a poor barber in England, after exercising his ingenuityon the perpetual motion, applied some of his devices to cotton spinning,and not only became one of the most opulent of manufacturers, but secureda place in the biography of eminently useful men.

Nearly all modern improvements and inventions have been broughtabout in a somewhat similar manner, and there are few but what mighthave been anticipated by attention to every-day facts. Suppose pressureengines had not yet been known: they might be developed by reflectingon a very common circumstance connected with ordinary pumps. Whenone of these no longer retains water in the cylinder and trunk, it is neces-sary to prime it, by pouring in a quantity sufficient to fill the space inwhich the sucker moves: this water resting upon the latter presses it down,and consequently raises the lever or pump handle, which again descends assoon as the water escapes below ; thus illustrating the principle by whichpressure engines act—the lever being moved by the water instead of the