1862.] 331 



battery, many of which require more time for verification than I at 

 present have at my disposal, but to lay before the Royal Society 

 certain novel results which I have obtained, and which I hope may 

 tend to elucidate, and possibly assist in explaining, the phenomena of 

 what is termed the stratified electrical discharge. 



7. I continue the practice I originally adopted of numbering my 

 vacuum-tubes * : during the progress of my experiments, I found that 

 the discharge of the battery was much more sensible to the slightest 

 variation of the state of tension in each of these tubes, than that of 

 the induction coil ; the sudden disruption in the discharge of the 

 latter presents greater obstacles to the more careful study of the 

 phenomena than is offered by the direct discharge of the battery. 



8. I soon ascertained that in some of my vacuum-tubes I was 

 enabled to study the action of the discharges under peculiarly 

 favourable conditions. I anticipate that these conditions may be 

 still further improved ; but, from the results I have already obtained, 

 I venture the opinion that it may be doubtful whether the true 

 theory of electricity as developed by the voltaic battery will be 

 correctly explained, unless by carefully experimenting with batteries 

 satisfactorily insulated. The battery I have described, with the im- 

 proved method of obtaining vacua, first suggested to me by Dr. 

 Frankland, offered me the opportunity of examining the discharge 

 under conditions heretofore unknown. 



9. The vacuum-tubes in which the experiments were made, and 

 which relate to the subject of this communication, were Nos. 70, 

 248, 315, 319, 320, 324 ^ These I shall refer to in the order of the 

 experiments. 



No. 248 (fig. 2 in woodcut) is about 2| inches long, 1 inch 

 diameter: to the platinum wires small balls of coke are attached, 

 about l^j- inch apart, the wires being protected inside the vacuum, 

 as far as the balls, by glass tubing. 



No. 70 (described Phil. Trans. 1859, p. 151) is 14 inches long, 

 with platinum wires 1 2 inches apart : a small glass bulb containing 

 crystals of iodine was placed in this tube before it was charged 

 with carbonic acid; and after the vacuum had been obtained, 



* Phil. Trans. 1859, p. 137 : the tubes were marked with consecutive numbers, 

 a note being taken of each as it was finally sealed. 



