G6 ANNUAL OF SCIENTIFIC DISCOVERY. 



thus finished, the jewels and pivots ai-e classified by means of a gauge 

 graduated so as to mark the difference of a ten-thousandth part of an inch. 

 The size of the pivots and jewelled holes are recorded at the factory, with the 

 number of each watch; so that if any one of cither should ever fail, in any 

 part of the world, its exact duplicate may be obtained at trilling cost by 

 sending the number of the watch to Waltham. All the other parts are made 

 faithfully alike, any given piece fitting one watch exactly as it does in 

 every other. Nothing is left to the eye or the touch of the workman, for 

 the machinery impresses its own unerring precision upon the whole. 



The mechanical principle of true time-keeping is the division of a constant 

 force in a given time, by means of perfectly adjusted mechanism, so arranged 

 as to change the rotary motion of the wheels into the vibratory motion of 

 the balance or pendulum ; the only mechanical difference between a clock 

 and a watch being, that the one is so arranged that it will move in one posi- 

 tion only, while the other will move in any, the pendulum setting the clock 

 in motion, and the balance performing the same service for the watch. The 

 escapement is that part of the time-piece which converts the rotary into 

 vibratory motion, as above, and is made by one tooth of the fastest running 

 wheel in the train escaping at each vibration, which wheel is known as the 

 " scape-wheel." The detached lever escapement, now used in the best 

 English watches, is the one adopted in the Waltham factory, with some 

 valuable modifications in the general construction of the movements. The 

 escapement varies indefinitely in movements of European manufacture, each 

 being fitted by hand to its particular watch, and useless in every other; while 

 in the American factory any one of a thousand escapements will accurately 

 fulfil its office wherever placed. All the ingenious tools by which these 

 remarkable results are obtained, were invented in this establishment, and 

 constructed within its walls. 



Having now a general idea of the skill and perfection requisite to success- 

 ful watch-making, and of the chief points of novelty in the Waltham estab- 

 lishment, let us proceed to a methodical examination of its varied operations. 



The factory building is of bride, two stories in height, surrounding a 

 quadrangle court, and covering about half an acre of ground. It accommo- 

 dates nearly a hundred and fifty operatives, many of them women- We 

 enter, first, the room devoted to the heavier and more massive machinery. 

 Here we find stamps arid dies, over a hundred in number, with which the 

 various pieces of the watch are first rudely stamped out of sheets of brass, 

 just as they come from the Connecticut rolling mills. We follow these 

 rough pieces (or " blanks," as they are technically named) to another 

 room, where they are reduced to proper size and form. 



Let us follow, for example, the fortunes of this barrel blank, a simple 

 wheel, about three-quarters of an inch in diameter, stamped out from a sheet 

 of brass three-sixteenths of an inch in thickness, and then hardened by 

 hammering. The blank is placed upon a lathe, on Avhich it revolves with 

 great velocity, and is brought in contact with a series of tools all fastened 

 immovably upon a frame. These speedily reduce it to the required size and 

 form, turn out the chamber to accommodate the main-spring, drill a hole in 

 the centre to receive the barrel arbor to which the main-spring is fastened 

 and around which it is coiled, and turn a flange on the outer edge, on the 

 periphery of which are to be cut the teeth to gear into the " train " of wheels 

 and set it in motion. All this is accomplished in less time than I take to 

 describe it, the machine setting itself, and invariably executing its work 



