Page:Encyclopædia Britannica, Ninth Edition, v. 24.djvu/420

W A T W A T but in Ireland the civil bill courts and courts of summary jurisdiction have co-ordinate authority to a limited extent. The law of waste as it affects ecclesiastical benefices will be found under DILAPIDATIONS. (4) Waste of assets or devastavit is a squandering and misapplication of the estate and effects of a deceased person by his executors or ad ministrators, for which they are answerable out of their own pockets as far as they have or might have had assets of the deceased. The legal liability of the representatives of the deceased is recognized by 30 Car. II. c. 7 and 4 W. and M. c. 24. In Scots law waste is not used as a technical term, but the respective rights of fiar and liferenter are much the same as in England. The latter, however, has not the right of continuing the working of existing mines unless the deed specially confers it upon him. Interdicts have in strong cases been granted against the sale of ornamental timber. In the United States, especially in the western States, many acts, such as the felling of timber, are not considered waste which would be waste in England. In some States waste is a cause of forfeiture; in some it gives a right to treble damages. The writ of estrepement is still in use. WATCH. Timepieces moved by a spiral spring instead of a weight were made as early as the 16th century, though the law which governs the mechanical theory of springs was first enunciated by Huygens in the 17th century (ut tensio sic vis) ; this, however, is not invariable. Fig. 1 shows the general arrangement of a watch or chronometer (both of which are here considered together). The barrel and fusee will be re cognized at once. The fusee is a sort of grooved hollow-sided cone ; the more rapid swell towards the thick end is re quired, because one turn of the fusee, when the chain is at that end, takes much more of it off the Fi s- 1 - barrel than at the thin end ; and on the assumption that the force of the spring varies as its tension the radius of the cone must increase more rapidly, in order to make the increase of leverage keep pace with the decrease in the force of the spring as it unwinds Avith an increasing velocity off the thick end of the fusee. The fusee itself is con nected with the great wheel by a ratchet and click and going ratchet (of which the spring and click are strongly shown in the figure), just as described under CLOCKS (vol. vi. p. 22). Something is also required to prevent the watch from being overwound, or the chain strained so as to break. This is done by means of a hooked lever, set on a hinge in the upper frame-plate (which is taken off in this drawing) ; and when the watch is nearly wound up the chain moving upwards reaches this lever, and moves it into such a posi tion that its hook catches hold of the long tooth projecting from the thin end of the fusee ; and thus the winding is stopped without any strain on the chain by the sudden check. By far the greater number of watches now made both on the Continent and in America have the mechanism known as the going barrel in substitution for the chain and fusee. In the going barrel the mainspring is of great length, and only a few coils of it are brought into action. To the going barrel itself the main wheel is attached, and thus the force of the mainspring is transmitted direct to the escapement. The general adoption of the going barrel mechanism is due to the introduction of keyless winding, which can only be adapted to the fusee Avatches with diffi culty, and to the greater cheapness of the arrangement. Moreover, it is found that for three or four coils of a long spring, at a certain degree of winding up, the tension varies very little. The going barrel is not used in the best English work, in Avhich absolute uniformity of motion is aimed at ; but for ordinary purposes it is not of so much consequence that the same rate from hour to hour should be maintained provided the daily rate is uniform. In Avatches Avithout a fusee the apparatus for preventing overwinding is different from that in the old form of Avatch ; it goes by the name of the Geneva stop, and the principle of it is simple. If two wheels Avork together, of Avhich one has the spaces between some two or more adjacent teeth filled up, it is evident that that Avheel camiot be turned quite round. And it Avill be the same thing if one of the wheels is only a cylinder with a single tooth in it, and the other has a certain number of notches, not going all round, through Avhich that tooth can pass. If, therefore, a one-toothed Avheel of this kind is fixed to the barrel arbor, which is turned by the key, and Avorks into a Avheel Avith only 4 or 5 notches in it and a blank space through Avhich the tooth cannot pass, it Avill evidently allow the barrel to be AA r ound up the 4 or 5 turns and no more; and as it unwinds it turns the stopping AA T heel back again Avith it. The other parts of a AA r atch do not differ from those of a clock, except in size, and the position in Avhich they are arranged, to bring them Avithin the circle of the dial, until Ave come to the escapement ; and there a different state of things arises, mainly from the fact that the balance of a AA r atch revolves through sometimes as much as 270, AA hile a clock pendulum only vibrates through 4 or 5. The balance being common to all the Avatch escapements, it will be proper first to describe that, and the conditions to AA T hich it is subject. The tAvo equal arms, Avith equal Aveights at each end, in fig. 3 of article CLOCKS (vol. vi. p. 17) are really a balance just as much as the Avheel which is commonly used as the more convenient form. But in that figure there is not to be seen that essential element of a modern balance the thin spiral spring, opening and closing itself at every vibration. The outer end of this spring is attached to the frame by a cock Pt (fig. 2), and the inner to the balance at S ; and the time of vibration depends only on the strength of the spring and the moment of inertia of the balance, and not at all upon the extent or angle of the vibration. And, as the force of a spring varies (ap proximately) inversely as its length, this suggests a ready method of regulating the waich ; for it is easy to make a pointer or index, or " regulator " PT, Fig. 2. turning on a ring fixed to the watch plate, concentric with the balance, and having two pins in it at P, called curb pins, just close enough together to embrace the spring, so that, as the index is moved one Avay or the other, the length of the spring which is free to A r ibrate may become shorter or longer. When the regulator has been moved as far as it can go towards fast, suppose, and the Avatch still loses, the spring has to be shortened at the cock R into which its outer end is pinned ; and, in order that the balance may be capable of alteration, so as still to stand square Avith the escapement Avhen the spring is in its neutral state, the other end is not actually pinned to the balance, but the cock S is on a small ring which is set on the axis or verge of the balance pretty tight by friction, but capable of being turned by hand. An index-plate like that in fig. 2 enables one to see smaller movements of the index than

radial marks.