Electric Residue in the Leyden Jar. 



487 



ing angles of deflection as the latter were dictated to him. The 

 following series of observations thus resulted, which in the third 

 column, under the title charge, contains the square roots of the 

 sines of the angles of deflection. 



Appendix II. 



Description and me of the Multiplier. 



A veiy strong copper damper of an elliptical form was sur- 

 rounded by 1000 coils of good copper wire about 0-25 millim. 

 thick, covered with silk, and coated with collodion ; the bed of 

 every coil was also well saturated with collodion. The ends of 

 the wires were led to clamping screws, which were cemented 

 with shell-lac into the same board that carried the multiplier. 

 In the elliptical opening of the damper, which was 8-5 centims. 

 long and 3-3 centims. high, a very strong cylindrical steel mag- 

 net 6 centims. in length and 1 centim. in diarneter was suspended 

 by means of a cocoon thread, stirrup and fork. The fork on 

 which the magnet hung carried a mirror, in order that observa- 

 tions might be made in magnetometer fashion. The whole was 

 well enclosed in a case provided with glass windows, so that the 

 needle could not be disturbed by currents of air. The damping 

 action was so strong, that oscillations of one degree elongation 

 were quieted in one minute. 



In using it for our purpose, one end of the multiplying coil 

 was connected by an intermediate wire with the outer coating of 

 the battery, which, besides this, was in good connexion with the 

 earth. The other end of the multiplying coil was connected 

 with the wire of a lever similar to that drawn in Plate VI. tig. 1 a, 

 though between them a glass tube tilled with water, and not too 

 short, was interposed. The discharge which deflected the mag- 

 net was eff"ected by the fall of the lever. The velocity with which 



