RECENT PROGRESS IN PHYSICS. 



365 



1 and 2, distilled water. 



3 and 4, distilled water + -} vol. sulpliuric acid. 



5, solution of sulphate of soda, reddened by acidified litmus. 



6, solution of sulphate of soda, made blue by litmus. 



Y, solution of sulphate of magnesia reddened by acidified litmus. 



8, solution of sul[>hate of magnesia made blue by litmus. 



9, distilled water reddened by acidified litmus. 

 10, distilled water made blue by litmus. 



Fis. 4. 



12 3 4 5 6 7 



Glass tubes, 3i inches long, and closed at one end around platinum 

 wires passing into them some distance, were filled with the respective 

 fluids and connected by means of the wires, (fig. 4,) ^as shown in 

 glasses 2 and 3, 4 and 5, 6 and Y, 8 and 9, while 1 and 2, 3 and 4, 5 

 and 6, 7 and 8, 9 and 10 were connected by wet cotton threads ; t\yo 

 of the above described tubes were placed, one in No. 1, the other in 

 No. 10. The wire of the tube in No. 1 was connected with the boiler, 

 and that of the tube in No. 10 with a leaden water pipe leading into 

 a well. 



As soon as the steam electric machine was put into operation, bubbles 

 of gas appeared upon all the wires, but upon the negative in exactly 

 double the volume of those upon the positive wire ; subsequent exam- 

 ination showed the former to be hydrogen and the latter oxygen. 

 After two or three minutes, the water in glass No. 9 became blue 

 around the wire, and that in No, 10, red; similar changes of color 

 appeared, but not so soon, in the solutions of glauber salt and of epsom 

 salt. 



The experiment was continued until the tension of the steam was 

 reduced from 75 to 40 pounds per square inch. The steam was then 

 shut ofi" and the boiler kept closed until the original tension was again 

 reached, when the experiment was repeated with the same result. 



In similar experiments, Armstrong carried the current through only 

 two glasses filled with distilled water, when the well knov/n phenom- 

 enon of the voltaic battery appeared ; the level in the glass contain- 

 ing the negative pole rose considerably, while it fell in the other. 



Another interesting phenomenon was then observed. When the 

 two glasses were filled to the brim with water, brought within 0.4 of 

 an inch of each other, and connected by a moistened silk thread, a 

 quantity of which was coiled up in the water of each, the following 

 phenomena were noticed: 



