XI. TIME. 91 



XI. MEASUREMENT OF TIME. 



444. Clock Dial. The hours, six only, are indicated by 

 perforated Roman letters. The hand or pointer is formed of a 

 revolving disc, painted in oil, with the subject of Aurora and 

 the Hours ; it must have gone round four times in 24 hours. 

 The dial is fitted in the original carved door of the clock. 

 Italian. 17th century. Rev. J. C. Jackson. 



445. Clock, in the shape of an orb of silver-gilt, covered 

 with silver filigree, suspended from a ring which is surmounted 

 by a cupid. The base of black marble is ornamented with 

 beads enriched with silver-gilt filigree, enamels, and precious 

 stones. German (Hamburg}. Dated 1685. 



Rev. J. C. Jackson. 



446. Clock 9 in gilt ormolu case, engraved with figures of 

 soldiers and festoons of flowers and fruit. It has a single hand, 

 and strikes the hours. The present pendulum has been sub- 

 stituted for the old bob. English. Early 17th century. 



Rev. J. C. Jackson. 



447. Two Chronometers, by Arnold. Royal Society. 



447a. Chronometer, with Glass Balance Spring. 



E. Dent. 



This is the invention and handiwork of the late Frederick Dent, of the Strand 

 and Royal Exchange, and the only specimen in existence. The spring requires 

 far less compensation for any given change of temperature than a steel spring 

 would, and the balance, which is composed of a glass disc, is compensated by 

 the two small compensation laminae mounted upon it. 



448. Chronometer Balance, " cut open " for action of heat 

 and cold ; ordinary construction without auxiliary. 



James Poole fy Co. 



449. Chronometer Balance, in rough state from casting. 



James Poole 3? Co. 



450. Pocket Chronometer, of silver, for inland observations. 



James Poole fy Co. 



451. English Keyless Mechanism. Models and specimens 

 of workmanship for fuzee and going barrel : J plate lever and 

 pocket chronometer movements. James Poole 8? Co. 



452. Keyless Watch, complete, with fuzee. 



James Poole $ Co. 



452a. Dipleidoscope with Telescope. M. Lutz, Paris. 



