WATCH. 332 WATCH. called the fork, -which is attached to the pallet. The action of the fork is controlled by the bal- ance-wheel by means of a little disk under the balance-wheel called the roller. On the outer edge of this disk is the roller pin. which alter- nately engages and releases the fork. It has al- ready been shown that the action of the hair- spring on the balance makes its vibrations iso- chronous; by means of the fork disengaging at regular intervals the teeth of the escape wheel from the pallet and so freeing the whole train, this isochronous motion is conveyed to the en- tire watch train. Fig. 4 of the accompanying cuts shows the action of the fork, roller, roller pin, pallet, and escape wheel, while Fig. 5 show3 ^-:ms^^ the hair-spring connected with the balance, with the roller and roller pin underneath. Watch M. ufactike. In England and Switzerland watch-making was early developed as a household industry. Among the Swiss, in particular, it gave employment to thousands of men, women, and children in their homes, the in- dustry being so far subdivided as to consist of over a hundred distinct branches ; and the Swiss finally became the watch-makers for the world. Various attempts, beginning as early as 1809, were made in the United States to make watches by hand after the Swiss plan: but the price of labor was too high and the laborers too inexperi- enced, so that each attempt ended in failure. The idea of manufacturing watches by using ma- chinery to make uniform and practically inter- changeable pieces, first occurred to Aaron Den- nison, a Boston watch-maker, about 1848. who was familiar with the methods and machinery employed for the manufacture of army mus- kets, at the I'nited States Armory at Spring- field, Mass. His original plan was to gather under one roof several labor-saving machines already in use in Switzerland for some of their watch-making processes; to supplement these by new contrivances; and to run them all by one power. He formed a small company, which built its first factory at Roxbury, Mass. But the Swiss authorities passed a law prohibiting the exportation of machines, models, or drawings, so that the pioneer company was obliged to con- struct its own machines. Its first macliinemade watch was turned out in IS.'j.S. Subsequently the works were removed to Walthani, Mass., where the company was reorganized under the name of the American Watch Company. It has been claimed for the watch-making in- dustry that it has caused the invention of a greater number of mechanical appliances than any other, with the possible exception of elec- tricity. Not only ingenuity, but the greatest ac- curacy and delicacy, is required of the machinery used "in watch-making. For instance, the finest screws used in a small-sized watch have a thread of 260 to the inch and weight 1/30,000 pound. The wire of a hair-spring, though a foot long, weighs 1/15,000 of a pound. The jewel work is extremely minute. A pallet jewel weighs 1/150,- 000 of a pound and a roller jewel much less. The advantages of producing all these minute parts by automatic machinery, besides cheapness and rapidity of production, are the greater accuracy of the parts and the possibility of replacing a broken part with an exact duplicate. The following is an outline of some of the principal processes : The plates which support the meclianism of the watch are turned on lathes and perforated for screws, arbors, and the like, by drills. The arbors, staffs, and pinions on which the wheels and other moving parts work are also turned on lathes. The teeth in the wheels and pinions are formed by cutters or by saws. The screws, big and little, are made by machines which cut the threads and finish the heads both for appearance and accuracy. The metal of the balances has to be compressed with great care to secuVe imiform density, by means of hammers or rollers. It must then be faced and recessed by lathes, tapped by drills, finished, and glossed. The springs are drawn, flattened, finished, and coiled by special machinery. Recently a branch of the watch-making in- dustry has been developed devoted exclusively to the production of low-priced watches. The pioneer among the low-priced watches was the Waterbury. which was patented by D. A. Bucke in 1S7S. Its cheap production was largely due to improvements in the old duplex escapement, which made it possible to stamp out its parts with an ordinary die. Within recent years some of the clock com]ranies have begun making low- priced watches as a by-product connected with clock manufacture. These cheap watches are made exactly like small spring clocks. The parts are stamped out. no jewels are used, and very little time is devoted to testing and adjust- ment. For watches of this type, of which the extreme of cheapness is the 'dollar watch,' which is probably sold at w-holesale for not more than 60 cents, an enormous demand has arisen. Most of these establishments are located in Connecticut and Xew York, and a single one of them had, in 1900, a daily output of 2000 watches. The manufacture of watch cases is now con- ducted by all better-grade manufacturers as a separate industry. The movements are made to standard sizes and qualities and then sold at wholesale to jobbers, and also to watch-ease manufacturers. The watch-case industry had a rapid development toward the close of the nine- teenth century and is now one of great impor- tance. Most of the work is performed by auto- matic machinery. Gold, silver, nickel, and gun metal are used, besides various alloys known un- der the trade names of silvcroid, nickel silver, etc. The popular goldlilled case was patented in 1859 by .lames Boss, of Philadelphia. Open-face watches have become very popular, thick beveled- edge glass rendering the case as reliable a pro- tection as the extra gold cover of the 'hunting' watch and more nearly dust-proof. Statistics. The following statistics, as pub- lished in the section on "Watches and Watch
