38 Dr. G. Gore. Chemico-Electric Relations of [Dec. 18, 



nected, by means of the wires beneath the base, with the two other 

 and ordinary vertical springs of the instrument, so that by turning 

 the handle they may be disconnected from the studs and connected 

 with those springs, and through them, the axis and standards, with 

 the voltaic cell, and receive a current in either direction, according to 

 the position of the handle. The sketch represents the handle and 

 axis in the above-mentioned first position, with the two wires of the 

 electroscope metallically connected together, but insulated from the 

 cell. 



The usual form of the electroscope I have employed is repre- 

 sented in fig. 2. A is a wooden base, B a wooden upright board 

 fixed to it. C is the situation of the reverser. D a microscope, 

 capable of vertical and horizontal movement, having a magni- 

 fying power of about 30 to 50 diameters, and provided with a 

 " spider-line." E is a grooved piece of wood fixed to the upright 

 stand. F a wooden slide, with a moveable scale, Gr, worked by a metal 

 rack H, and pinion with handle, I. J is the capillary, supported by a 

 perforated little brass shelf , K. L is the pressure- chamber. M the 

 glass tube containing the compensating column of mercury. 1ST a 

 thin glass tube, about 5 millims. bore, containing the mercury and 

 conducting solution. O and P are the terminal platinum wires for 

 attachment to the screws of the reverser. Q is a strong clip, shown 

 separate from the instrument. K. is a metal support for the clip. S 

 is a moveable slide of cork, carrying a very fine hair, T, for indicating 

 the position of the meniscus. It is not usually necessary to measure 

 the amount of movement of the meniscus. Some cotton wool is 

 placed in the cup, U, and the cup is covered with a lid to exclude 

 dust. A strip of white paper is affixed behind the capillary portion 

 of the tube to form a white background, and the instrument requires 

 to be used in a good light. 



Having found by additional experiments that in certain cases the 

 mercury moves in an opposite direction to the electric current, I am 

 now engaged in examining that fact, and in completing an investi- 

 gation of the causes and conditions of the movements. 



VII. " Chemico-Electric Relations of Metals in Solutions of Salts 

 of Potassium." By G. Gore, LL.D., F.R.S. Received 

 December 8, 1879. 



The following experiments were made with the object of determining 

 the chemico-electric positions of various metals, &c, in solutions of 

 salts of potassium of various strengths, and at different temperatures ; 

 and also with the intention of ascertaining, by the aid of Lippmann's 



