Ellectromotive Forces in the Voltate Cell. 165 
Fig. 6.—Diagram of Pellat’s Method. 
Légende. 
KL, compensateur. m, interrupteur. 
C, curseur. F, feuille dor. 
R, rhéostat. A et A’, plateaux attractifs de 
P, piles Daniell fournissant le l’électroscope. 
courant du compensateur. 6b, batteries de 100 volts chacune 
p'p, plateaux du condensateur pour charger les plateaux 
(p fixe, p’ mobile). AA’. 
The diagram, fig. 6, pretty well explains itself. The contact at m is 
broken the instant before p’ is raised. 
Fig. 7.—Pellat’s Condenser. 
Fig. 7 shows how this was done in practice. Pulling the string, A, raises 
a sliding-pin with a shoulder, g, fixed to it a millimetre below the bar, B. 
The pin thus first breaks contact near H, and then raises the hinged 
bar BB, to which the upper plate, M, is attached. The upper plate, 
being always in connection with a battery, requires no special insula- 
tion, The lower plate is carefully supported by a Thomson insulator, I. 
The lower plate was considerably smaller than the upper one, and it 
was further protected from stray inductions by aguard-screen. Screws, 
ec, served to regulate the distance between the plates. 
