HOROLOGY 



7*9 



inversely a the distance of it* weight* from the 

 centre, lint inversely an tlie mjtmn- of tin- li-tam-c 

 of the centre of gyration from the centre of motion. 



The particular 

 IHIIHI-. in the 

 case of any 

 chronometer 

 are matter of 

 .nl j uHt inent. 

 For instance, 

 one chrono- 

 meter may be 

 made to go 

 Fig. 16. accurately in a 



temperature of 



40, and also in a temperature of 80 , at other 

 temperatures being not so accurate; another 

 eli ronometer to go accurately at a temperature 

 of 20 and 60. It is manifest that the former 

 would be adapted to voyages in a warmer, the 

 latter to voyages in a colder climate. To more 

 fully adjust the compensation certain pieces are 

 li\fd to the balance to act in heat or in cold, and 

 this is called auxiliary compensation, and there are 

 at least two or three balances invented of recent 

 years, one of which is shown in fig. 15, which are 

 practically self-adjusting for the ordinary range of 

 temperatures to which marine chronometers are 

 subjected. The solution of the problem seems to 

 be in setting the laminae flat instead of vertical, 

 ami making the bar also bimetallic. 



Apparatus for testing chronometers have been 

 long in use in the observatories at Greenwich and 

 Liverpool. In the latter there is now an extensive 

 apparatus for this purpose, devised by the ingeni- 

 ous astronomer, Mr Hartnup. In a room which 

 is isolated from noise and changes of temperature 

 the chronometers are arranged on a frame under a 

 glass case, so contrived that they may be subjected 

 in turn to any given degree of temperature. The 

 rate of each under the different temperatures is 

 observed and noted, and the chronometers regis- 

 tered accordingly. 



A large proportion of modern watches are made 

 to wind and to set the hands from the pendant. 

 Fig. 16 shows the form of keyless work chiefly 

 employed in English non-fusee watches. The 

 chief part is the three wheels working in the 

 rocking-bar ab, one of which gears with the wind- 

 ing-wheel, d, of the barrel when the rocking-bar, 

 which is capable of a little motion, is in its normal 

 place, as in the fig. A contrate wheel is fixed on 

 the end of the winding-button c, and by its means, 



when the but- 

 ton is turned, 

 the train is 

 set in motion 

 and the barrel 

 wound. When 

 the hands are 

 required to be 

 set, a I'M -I i 

 piece in the case 

 hearing on the 

 end, b, of the 

 rocking-bar 

 is pressed by 

 the finger, tak- 

 ing the rock- 

 ing-bar wheels 

 out of gear 

 with the wind- 

 ing, and put- 

 ting them in 

 gear with the 

 hand -wheels at 

 The hands 



push-piece being let go, the train return* to it* 

 normal position. The use of the funee being at- 

 tended with Home amount of complication in the 

 ki-ylfss iiii-cliaiiism, it in usually dipen*ed with 

 on thin account, and one of the moMt modern 

 arrangement* in an English keyletw watch in 

 shown in li^- 17. The barrel, n, is here made to 

 occupy all the 

 height lift \\-fi-n 

 the pillar (or 

 lower) plate and 

 the top limit of 

 the movement, 

 and all the space 

 between the cen- 

 tre pinion and the 

 balance cock, in 

 order to get a 

 long, thin main- 

 spring ; the ad- 

 vantage of which 

 is that there is 

 an abundance of 

 power (much 

 more than is re- 



Fig. 17. 



Fig. 10. 



.y then l>e turned by the winding button, and, the 



quired fora day's going), and only a portion of the 

 spring is used for the ordinary winding for twenty- 

 four nours. This practically insures an adjust- 

 ment of the motive power as nearly equal to that 

 obtained by the use of the fusee as it is possible to 

 arrive at. 



Repeating watches were first made about 1676, 

 the invention being claimed by Daniel Quare, 

 Edward Barlow, and Tompion. They have a 

 striking arrangement very much on the principle 

 of the striking-clock, and on compressing a spring 

 they at any time strike the hours and quarters, 

 and in some cases the minutes. They are very 

 expensive and liable to go out of repair, and repairs 

 are costly. They have nearly gone out of use. 

 For stop-second arrangements to record swift 

 passing events, see CHRONOGRAPH. 



In England watches are mostly made at Preston, 

 Liverpool, Coventry, and at Clerkenwell, London, 

 where the division of labour principle is carried 

 out in an extreme degree many small factories 

 making, for instance, only balances, others springs, 

 others cases, others hands, &c., only that small 

 number who put the works together seeing the 

 complete watch. At Kew Observatory there are 

 arrangements for testing watches, and grant- 

 ing certificates if satisfactory, on payment of a 

 fee. In the United States the manufacture of 

 watches, like that of clocks, is carried on in a 

 much more wholesale manner ; the wheels and 

 plates Ijeing stamped by machinery, every similar 

 part being exactly alike and interchangeable ; and 

 on account of the economy of manual labour, 

 they can be turned out marvellously cheap. 

 Generally the large clock-factories also manufacture 

 watches. 



See Thioue 1'aine. TraM cTHorlogerie (1741) ; Ix-pau to, 

 Traite d 1 Horlogerie ( 1755 ) ; F. Berthoud, Trait* da HOT- 

 loyet Marines ( 1773), Histoire de la Mesiire du Tempt par 

 Its Horlotjes (1802) ; Thou. Reid, Treatise <>n Clock ami 

 Watch Making ( 1819) ; Jiirgensen, FHncipes de la Mtsure 

 du Temps (1838); Moinet, tfoureau Traitt gfn> ral 

 d'Horlogerie (1848); Wood, Curiositiei of Clocks an-l 

 Watches (186fi); Deniaon (afterwards known as Sir 

 E. Beckett and then as Lord Orimthorjie ), Treatise 

 on Clocks <i't tt'iitclusanil K<II* (1*74; Ttln-cl. ! 

 books by J. F. Ken.lul (1SH2) an<l F. .1. I'.Mtt.'ii 

 ( 1894 ) ; Sauuier, Modtrn Horoloijy ( Kng. trans, by 

 Tripplin & Rigg, 1885) ; Rombol, E**n<memetit thcorioue 

 de V Horltxjene ( Geneva, 1889); Britten, Watch /../ 

 Clock Maker? Handbook ( 1889) ; The British Horoloincal 

 Journal ( monthly from 1889) ; La Revue Ckronomttriqut 

 (monthly from 1857). 



Horoscope. See ASTROLOGY. 



