432 Messrs. Wanklyn and Cooper on Hydrogen Gas. 



A repetition of the experiment in which potash was added 

 to the solution of the ferricyanide, and with exposure to bright 

 sunlight, showed no absorption of hydrogen during a period of 

 eight days. 



IV. Nitric acid (spec. grav. 1*42) was tried. An exposure 

 of hydrogen for sixteen hours to the action of the acid pro- 

 duced no change in the volume of the gas, and on exami- 

 ning the gas it was found to be devoid of nitric oxide. 



V. A mixture of oil of vitriol and strong nitric acid was 

 altogether without action on the gas. 



VI. Aqua regia was also tried and found to be without 

 action on hydrogen. In this case the volume of gas was 

 gradually increased, viz. from 67*5 up to 110 cubic centim. 

 The increase was due to evolution of chlorine. On washing 

 with water the chlorine was dissolved, and there remained 

 66*5 cubic centim. of hydrogen which burnt in a satisfactory 

 manner. This experiment was made in diffused daylight ; in 

 bright sunlight reaction between the chlorine and the hydrogen 

 must take place. 



VII. Even solution of chromic acid was found to be with- 

 out action on hydrogen at ordinary temperatures. The 

 duration of the exposure was twenty-four hours, and the 

 readings were : — 



, Volume of hydrogen before . . 64*8 cubic centim. 

 „ „ after . . 65*0 „ „ 



The activity of hydrogen is illustrated as follows : — 

 When solution of permanganate of potash — whether it be 

 strongly alkaline, or neutral, or strongly acid — is brought into 

 an atmosphere of hydrogen, it is attacked by the hydrogen 

 even at ordinary temperatures. The rate of the action depends 

 upon a variety of circumstances which we are carefully 

 studying. 



In one experiment the Hempel gas-pipette was charged 

 with a solution containing about 30 per cent, of caustic potash 

 and about 2 per cent, of permanganate of potash. The 

 readings were : — 



Vol. of 



gas 



taken 



. • . 



65 cub. 



cent. 



on June 24, 



5J 





after absorption 



46 



?.? 



28, 



)> 





V 



J? 



35-8 



n 



July 2, 



>> 





V 



» 



33-2 



y, 



» 3, 



5) 





5? 



J) 



26-8 



V 



» 6, 



» 





JJ 



)> 



21-4 



» 



10, 



11 





>J 



■)•} 



19-5 



J? 



12, 



