434 



CATALOGUE.— EX-ECTRlCAt APPARATUS. 



Cadet's electrometer. Ann. Ch. XXXVII. 



68, Nich. V.31. 

 Marechaiix's delicate electrometer. Gilb. 



XV. 98. 



Microelectrometers. 



Condensers, Multipliers, and Galvanometers. 



Volta on rendering sensible small degrees 



of electricity. Th. tr. 1782. 237- 

 Volta on the advantage of an imperfect in- 

 sulation. Roz. XXII. 325. XXIII. 381. 

 Soc. Ital. V. 

 Bennet's electrometer with a condenser. Ph- 



tr. 1787. 32. 



A plate of marble on the electrometer, and on this a 

 imall plate of metal. 



Bennet's doubler of electricity. Ph. tr. 1787. 

 288. 



Merely varnished plates laid on each other. Liable to the 

 inconvenience of contracting a permanent charge. 



Dumotiez's condenser. Roz. XXXI. 431. 

 Cavallo on measuring small quantities of 

 electricity. Ph. tr. 1788. 1. 



Found many accidental errors from permanent charges, 

 even when the plates of the instruments had been untouched 

 for a month. To illustrate this, he made experiments on 

 the decreasing progression of the vslocity with which the 

 Huid escapes. 



Cavallo's multiplier. Nich I. 394. 

 Cavallo's collector. Ph. tr. 1788. 255. Roz. 

 XXXIV. 258. 



Consisting of a fixed plate between two moveable ones. 



Nicholson's revolving doubler. Ph. tr. 1788. 



403. Nich. II. 370. IV. 95. 



Some thin plates at the distance of -^ of an inch from 

 each other had their capacity augmented lOO times. This 

 instrument was intended for producing electricity from the 

 charge which is almost inseparable from the plates, 

 and usually gave a spark when turned lO or 20 times. 

 It pumps out positive or negative electricity from a 

 ball into two fixed plate s,by means of a revolving plate; the 

 redundant electricity contained in either of the fixed 

 jlates is attracted to one of them by the revolving plate, con- 

 nected with the ball; all the communications are then de- 



stroyed, and the revolving plate, with a charge equal and 

 opposite to that of the first fixed plate, is brought opposite 

 to the second, while this is connected with the ball, and 

 acquires from the ball a charge nearly equal to that of the 

 first plate : so that the redundant electricity of each of the 

 fixed plates is now nearly equal to what they both contained 

 at first, and the charge is nearly doubled by each turn. 



On the doubler of electricity. Journ. Phys. 

 XLV. (II.) 463. 



A Microelectrometer. Nich. I. l6. 



Read on the invention of the doubler. Nich. 

 II. 495. 



Cuthberlson on Read's condenser. Nich. 

 Gilb. XIII. 208. 



Pepys's galvanometer. Ph. M. X. 38. 

 Of gold leaf. 



Gilbert and Bohnenberger on microelectro- 

 meters. Gilb. IX. 121,158. 



Weber's glass condenser. Gilb. XI. 344. 



Indicated the electricity of ice on the Danube. 



Hacliette and Desormes's improved doubler. 



B.Soc. Phil. n. 83. Gilb. XVII. 414. 

 Marechaux's electromicrometer. Gilb. XV. 



98. XVI. 115. 



With a screw and silver leaf. 



Wilson's condenserand doubler. Nich. IX. 19. 



Regulators and Dischargers. 



Lane's electrometer. Ph. tr. 1767. 451. 

 Cuthbertson's measurement by explosion. 



Nich. II. 215. 

 Lawson's discharging electrometer. Ph. M. 



XI. 251. 

 Von Hauch's discharging electrometer. Ph. 



M. XI. 267. 



Gilb. XIV. 257. 



Volta says, that Lane's electrometer agrees with Henley's 

 in all its indications. 



Distim'uhhers. 



Chappe on a mode of distinguishing electri- 

 city. Roz. XXXIV. 62. 



Nicholson on instruments for the distinctioD 

 of electricity. Nich. 8. HI. 121. 



