1879.] 



The Chloride of Silver Battery. 



283 



gas contained in the cylinder occurs on connecting the metallic 

 disks with the battery by means of the contact-key. The edges of the 

 cylinder were rubbed with grease, and care was taken to prove that 

 the apparatus was perfectly tight, by causing the fluid in the limb of 

 the gauge to stand for some time higher than that in the bulb. When 

 contact was made with a battery of 9,800 cells, there was not the 



Fig. 1. 



slightest indication of any alteration of volume of the contained air, 

 so that there was neither condensation about the disks which would 

 have caused a contraction, nor repulsion from the disks which would 

 have caused an expansion of volume. The fluid in the stem was 

 observed with a lens, but not the slightest motion of it took place. 

 The same result was noticed even when water was substituted for 

 sulphuric acid. So far, then, as this apparatus would indicate it, the 

 result is entirely negative. 



Potential necessary to produce a discharge between disks at a constant 

 distance and at various pressures. 



The experiments were made by placing the micrometer- discharger, 

 Part I, fig. 1, under a bell-jar, and in the first instance adjusting the 



x 2 



