Page:Encyclopædia Britannica, Ninth Edition, v. 6.djvu/23

Rh caused by his enemies gave it full scope. This great man, who fell short only of the highest form of moral greatness on one supreme occasion, but who did more for his country than any soldier till Wellington, and more for the people and princes of India than any statesman in history, died by his own hand, November 22, 1774, in his fiftieth year. The portrait of Olive, by Dance, in the Council Chamber of Government House, Calcutta, faithfully represents him. He was slightly above middle-size, with a countenance rendered heavy and almost sad by a natural fulness above the eyes. Reserved to the many, he was beloved by his own family and friends. His encouragement of scientific undertakings like Major Rennell s surveys, and of philo logical researches like Mr Gladwin s, was marked by the two honorary distinctions of F.R.S. and LL.D.

1em        HE origin of clock work is involved in great obscurity. I Notwithstanding the statements by many writers that clocks, horologia, were in use so early as the 9th century, and that they were then invented by an archdeacon of Verona, named Pacificus, there appears to be no clear evidence that they were machines at all resembling those which have been in use for the last five or six centuries. But it may be inferred from various allusions to horologia, and to their striking spontaneously, in the 12th century, that genuine clocks existed then, though there is no surviving description of any one until the 13th century, when it appears that a horologiuni was sent by the sultan of Egypt in 1 232 to the Emperor Frederick II. &quot; It resembled a celestial globe, in which the sun, moon, and planets moved, being impelled by weights and wheels, so that they pointed out the hour, day, and night with cer tainty.&quot; A clock was put up in a former clock tower at Westminster with some great bells in 1288, out of a fine imposed on a corrupt chief-justice, and the motto Discite justiliam, moniti, inscribed upon it. The bells were sold or rather, it is said, gambled away, by Henry VIII. In 1292 one is mentioned in Canterbury Cathedral as costing 30. And another at St Albans, by R. Wallingford the abbot in 1326, is said to have been such as there was not in all Europe, showing various astronomical phenomena. A description of one in Dover Castle with the date 1348 on it was published by the late Admiral Smyth, P.R.A.S., in 1851, and the clock itself was exhibited going, in the Scientific Exhibition of 1876. In the early editions of this Encyclopaedia there was a picture of a very similar one, made by De Vick for the French king Charles V. about the same time, much like our common clocks of the last century, exeept that it had a vibrating balance, but no spring, instead of a pendulum, for pendulums were not invented till three centuries after that.

EB9 - Clocks - Fig. 1.png .—1. Section of House Clock.

The general construction of the going part of all clocks, except large or turret clocks, which we shall treat separ ately, is substantially the same, and fig. 1 is a section of any ordinary house clock. B is the barrel with the rope coiled round it, generally 16 times for the 8 days ; the barrel is fixed to its arbor K, which is prolonged into the winding square coming up to the face or dial of the clock ; the dial is here shown as fixed either by small screws x, or by a socket and pin z, to the prolonged pillars p, p, which (4 or 5 in number) connect the plates or frame of the clock together, though the dial is commonly, but for no good reason, set on to the front plate by another set of pillars of its own. The great wheel G rides on the arbor, and is connected with the barrel by the ratchet R, the action of which is shown more fully in fig 1 4. The intermediate wheel r in this drawing is for a purpose which will be de scribed hereafter, and for the present it may be considered as omitted, and the click of the ratchet R as fixed to the great wheel. The great wheel drives the pinion c which is called the centre pinion, on the arbor of the centre whee.1 C, which goes through to the dial, and carries the long, or minute-hand; this wheel always turns in an hour, and the great wheel generally in 12 hours, by having 12 times as many teeth as the centre pinion. The centre wheel drives the &quot; second wheel &quot; D by its pinion d, and that again drives the scape-wheel E by its pinion e. If the pinions d and e have each 8 teeth or leaves (as the teeth of pinions are usually called), C will have 64 teeth and D 60, in a clock of which the scape-wheel turns in a minute, so that the seconds hand may be set on its arbor prolonged to the dial. A represents the pallets of the escapement, which will be described presently, and their arbor a goes through a large hole in the back plate near F, and its back pivot turns in a cock OFQ screwed on to the back plate. From the pallet arbor at F descends the crutch F/, ending ic the /or/;/, which embraces the pendulum F, so that as the pendulum vibrates, the crutch and the pullets necessarily vibrate with it. The pendulum is hung by a thin spring S from the cock Q, so that the bending point of the spring may be just opposite the end of the pallet arbor, and the edge of the spring as close to the end of that arbor aa possible a point too frequently neglected.