456 
LORD RAYLEIGH AND MRS. H. SIDGWICK ON THE 
Explanation op Plate. 
PLATE 17. 
Fig. 1. A. Principal battery of Grove’s or storage cells. 
B. Resistance for adjustment of current. 
C. Voltameters. 
D. Bough tangent galvanometer. 
E. Reversing key of current weighing apparatus. 
F. Fixed coils. 
G. Suspended coil. 
H. K. Mercury cups, into which dip the terminals of resistance R. 
L. Earth connexion. 
M. Leclanche’s of E.M.F. compensator, 
N. 0. Resistance-boxes of same. 
P. Standard galvanic cell. 
Q. Galvanometer commutator. 
S. Associated resistance of 10,000 ohms. 
T. Galvanometer. 
Fig. 2. Section of ebonite ring (full size). 
Fig. 3, § 14. Connexions for comparison of galvanometer constants. 
A. Daniell cell. 
B. Mercury reversing key. 
C. Point where current divides. 
D. Coil of electro-dynamometer. 
E. Ebonite coil. 
F. H, L, M. Mercury cups. 
G. Bridge galvanometer. 
K. Ptesistance-box in multiple arc with [ 1 Oj. 
P. Short circuiting piece to connect F and H. 
N. Resistance added to E. 
Fig. 4, § 24. Curves of current weighings. In the original drawing two divisions 
along the line of abscissae represent one minute, and two divisions 
along the line of ordinates represent one milligram. Of these 
divisions every tenth only is shown in the Plate. 
