MESSRS. W. DE LA RUE AXD H. W. MULLER ON THE 
as the average of a great number of experiments, the hyperbola coincides closely with 
the observations, while in that of plane surfaces, for which only a few experiments 
were made, the coincidences are not so perfect. Nevertheless, it would appear that 
Fig. 78. 
the law of the hyperbola holds equally well for a constant pressure and varying 
distance as it does for a constant distance and varying pressure ; the obstacle in the 
way of a discharge being as the number of molecules intervening between the terminals 
up to a certain point. 
In the two cases of spherical and plane surfaces the ratio between the transverse 
and conjugate axes of the respective hyperbolas laid down on the scale adopted— 
For spherical surfaces CV=38'87 _ 
CB = 32T6~ “ ° I 
ny— 0 Q .4 Mean 1 267. 
^ _ 1 .O Q ^ 
discs . 
