to the Contact of Gases with Liquids. 63 



through which the hydrogen passed decided the sign of the 

 electrification. From hydrochloric acid it was positive; from 

 acetic acid (or it may be acetate of sodium) it was negative. 

 Even the very whimsical deflexions from sodium and water 

 become intelligible. As a piece of sodium careers about on 

 the surface of water, the escaping hydrogen is one instant in 

 contact with water, the next with, caustic soda, the next with 

 the side of the vessel, and, accordingly, on the theory of 

 contact, the irregular deflexions are at once explained. 



In most of the experiments described above, the hydrogen 

 was allowed to escape from an open dish or beaker, and not 

 from a narrow delivery-tube, for it was found that the gas 

 partially discharged itself when it passed through narrow 

 openings. Whatever tended to electrically connect the 

 charged liquid with the oppositely charged escaping gas, also 

 tended to lessen the charges on both. And besides this, there 

 was the possibility that the contact of the gas with the de- 

 livery-tube might cause electrification. On the whole, it was 

 found least ambiguous to half fill an evaporating-dish about 

 6 inches in diameter and 2 inches high with HC1 and drop 

 into it a few fragments of zinc. The bubbles of gas then shot 

 straight up through the middle of the liquid, and passed into 

 the air without coming into contact with anything else. It 

 was, however, a defect of this mode of proceeding that par- 

 ticles of the acid were projected about in all directions, some- 

 times beyond the dish. In order to get rid of any doubts on 

 this head, a smaller dish was used and placed at the bottom of 

 a beaker 7 inches high. I propose to give in detail one of 

 several experiments made in this way with all possible care. 



The electrometer was not in a very sensitive state. The 

 high-resistance Daniell gave a deflexion of 38 divisions on 

 either side. A glass beaker 7 inches high and 5 inches in 

 diameter was placed on the insulated plate. A porcelain dish, 

 2f inches in diameter and 1^ inch high, was nearly filled 

 with a 10-per-cent. solution of HOI in distilled water, and 

 placed at the bottom of the beaker just mentioned. Three 

 small fragments of zinc were now dropped into the dilute acid in 

 the small dish. A very slight effervescence at once appeared, 

 and it gradually increased, but never became violent. No 

 trace of spray could be detected at the end of the experiment 

 above the lower half of the beaker. In 4 minutes from 

 dropping the zinc, the spot could be perceived moving, and 

 in 4^ minutes more it had moved 28 divisions to the left, 

 indicating the charge on the dish negative. I append the 

 notes taken during the time the experiment lasted. 







