Short Cuts in Engineering.
Rock may be so hard as to withstand a drill of the hardest steel; then the engineer pours an acid of the necessary dissolving power. A water pipe may freeze at a point difficult of access; it is thawed by the warmth created by an electric current. A surveyor has to reduce to square feet the irregular area of a factory site or a garden plot; around the edge of his diagram he runs a planimeter, it tells him automatically what surface it has surrounded in its excursion. If he has no planimeter, a delicate balance will serve just as well. Let him take a piece of paper, uniform in thickness, and cut it into the shape of the area in question. In weighing the diagram with care he learns its superficies because he knows the weight of each square inch or foot of the paper. Pumps for ages have exercised the wit of inventors who have devised wheels, screws, pistons, and scoops of every imaginable form. M. Giffard boldly discarded all moving parts whatever and in his injector, actuated directly by a blast of steam, provided a capital means of sending water into a boiler.
A generation ago engineers of eminence were attempting the transmission of energy in a variety of ways. Ropes and wire cables were installed for considerable distances in Germany and Switzerland; in France there was an extensive piping of compressed air, still in evidence at the capital; and water under high pressure is to some extent to-day employed in London. All these schemes, together with the old methods within a shop itself of taking motion from motor to machine by belt or chain, have been wiped off the slate by the electrical engineer. With a tax of the lightest he carries for many miles in a slender wire a current whose energy takes any form we please,—not only mechanical motion, but chemical action, light or heat. Can simplification go farther than this, or the future hold for us another gift as golden?