33G [Dec. 18, 



Depressing the wire very gradually, the discharge assumes the form 

 of fig. 7, the positive being sharply defined, the negative retaining 

 much of its irregular termination, but each separated from the other 

 by a dark interval of about one inch in length. 



As the wire was further depressed in the water, the brilliancy of the 

 positive and negative luminous glows increased ; and when about 



3 inches of one wire had been immersed in the water, a single clearly 

 defined luminous disk burst forth from the positive, remaining steady 

 and apparently fixed as in fig. 8. 



As the wire was again further depressed, the luminous discharge 

 at the positive slowly progressed along the tube until another bright 

 disk appeared, remaining (as long as the wire was not further de- 

 pressed) stationary as in fig. 9. At this time 13 inches of wire 

 were in the water. 



The resistance was again reduced by depressing the wire to 1 6 

 inches, when a third luminous disk was developed as in fig. 10 ; and 

 at 18 inches depression, or the entire length of one column of water, 

 a fourth disk was observed as in fig. 11. 



In this state, while the four luminous disks were stationary, the 

 wire attached to the positive terminal of the battery was depressed 



4 inches ; the luminous disks gradually closing on each other became 

 more compressed, when a fifth was developed, fig. 12. 



The luminous glow on the negative ball had gradually assumed a 

 flattened surface towards the positive, appearing as a ring of light ; 

 depressing the wire to 7 inches in the water, the luminous disks closed 

 but remained separate, and a 6th was observed ; with 1 1 inches de- 

 pression another, or the 7th, appeared, the negative glow increasing in 

 brilliancy, retaining its flattened appearance. At this time, probably 

 from the long- continued action, the power of the battery was re- 

 duced, arid the 7th disk disappeared, retreating to arid apparently 

 absorbed by the luminosity on the positive ball; but on further 

 depressing the wire, it was immediately reproduced ; and on 1 5 inches 

 insertion an 8th was obtained, the negative glow increasing in 

 brilliancy, and the part nearest the positive presenting a still more 

 flattened appearance. 



Another clearly defined and separated disk of light was elicited, 

 and then three or four came out in quick succession ; the whole dis- 

 charge now became unsteady and flittering, the luminous disks no 

 longer remaining fixed or stationary. 



