XI. TIME. 117 



462. Model of a Clock with four Faces, to be worked 

 by water. Major M. L. Taylor, R.A. 



463. Sir W. Congreve's Clock, in which the action of 

 the pendulum is replaced by the motion of a small steel ball on an 

 inclined plane, which it descends in 30 seconds. 



Major M. L. Taylor, R.A* 



486. Month Equation Clock, with double pendulum and 

 dead-beat escapement by Quire, showing minutes and seconds both 

 sidereal and mean time, also sun fast or slow, and containing an 

 annual almanack, mentioned in Cooke & Maule's account of 

 Greenwich Hospital in 1789. Royal Naval College, Greenwich. 



447. Two Chronometers, by Arnold. Royal Society. 

 These chronometers were taken round the world by Captain Cook. 

 447a. Chronometer, with Glass Balance Spring. 



E. Dent and Co. 



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. Explanation of the principles of action of the Com- 

 pensation Balance, with four models showing the various 

 stages of construction. James Poole ? Co. 



*' Cut open " for action of heat and cold ; ordinary construction without 

 auxiliary, in rough state from casting. 



450. Silver Pocket Chronometer. James Poole $ Co. 



451. Diagrams and Models of the method of winding and 

 setting watches without a key. James Poole fy Co. 



452. Keyless Watch, complete, with fuzee. 



James Poole fy Co. 



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



453. Keyless Watch, complete, with centre seconds and 

 going barrel. James Poole $ Co. 



454. Ship Chronometer (2 day), complete. 



James Poole fy Co. 



455. Ship Chronometer (2 day). Movement reversed, to 

 show workmanship. James Poole fy Co. 



456. Chronometer Movement (2 day), as received from 

 the factories in Lancashire. James Poole ty Co. 



456a. Six Chronometers with rates froni the Geneva Obser- 

 vatory, stating records of trials of the years 1875 and 1876. 



H. R. Ekegren, Geneva. 



