396 



202 exhibited a remarkably well-defined cloud-like discharge, the 

 several clouds being clearly and distinctly separated. In 219, the 

 appearance of the discharge in this tube was similar to that in fig. 3 A, 



Fig. 3 A. 



with a particularly brilliant glow around the negative ball, but without 

 any stratifications from the positive. 



Having thus described the appearances of the induced discharge in 

 these tubes, I now proceed to the description of experiments made 

 in the same vacua, 1st, with the water- battery of 3520 cells; 2ndly, 

 with the 5 1 2 series of Daniell's constant battery ; and lastly, with 400 

 series of Grove's nitric acid battery. 



With the water-battery, as I have stated in my previous commu- 

 nication, the stratified discharge, similar in character to that of the 

 inductive coil, was obtained, not only in 146 and the other tubes, 

 but also through 146 and any one of the others at the same time. 



From the risk of fracture, I have not ventured again to heat the 

 potash in 146, but I have invariably found that whenever the potash 

 in any of the other tubes was heated, the discharge from the water- 

 battery, instead of increasing in distinctness and brilliancy, entirely 

 ceased. 



The discharge from the water-battery through each of the tubes 

 had the appearance of being continuous, and the needle of the 

 galvanometer, placed on the circuit, showed a steady deflection. 

 To test whether the discharge was continuous, I attached No. 219 to 

 my rotating apparatus (Philosophical Transactions, 1859, part 1. 

 p. 158) ; the discharges were then clearly separated, so that even 

 with this apparatus they were shown to be intermittent. 



As the water in the battery, after a lapse of some weeks, had 

 partially evaporated, the action was so reduced that it would no longer 

 pass through any of the vacuum-tubes except 219, in which it 

 assumed the appearance as in fig. 3 B. In this state it remained for 

 three or four weeks, and whenever from change of temperature moisture 

 was deposited on the surface of the glass tubes, the luminous discharge 



