141 



hydrogen. In this series the hydrogen passed through the solution for only 

 four hours. Little or no reduction occurred except when the platinum was 

 made the negative electrode from a hattery. Then reduction was quite 

 rapid. 



When zinc dust or platinum l)la<k was sus[)ended in the liquid and 

 hydrogen passed in the reduction anproached the rapidity due to nascent 

 hydrogen. 



Similar ex])erimcnts were carried out using carbon instead of plati- 

 num. New arc-light carbons were purified by first soaliing them in acid and 

 then heating tliem to redness for twenty minutes. Tliey were then 

 placed in a solution of acidified potassium dichromate until no reduc- 

 tion of the latter was observed. After thorough washing they were bound 

 into a bundle and used in tlie same i^ay as were the zinc rods. In the 

 aipieous solution containing the car))ons hydrogen produced little or no 

 reduction of the dichromate in four and one-half hours. When the carbons 

 were made the negati\'e electrode from a battery reduction was complete 

 in from fifteen to thirty minutes. 



Finely divided carbon suspended in the solution of dichromate did not 

 increase the reducing power of hydrogen led into the solution. 



An attempt was made to duplicate the conditions for the production 

 of nascent hydrogen by having both zinc and acid in the dicliromate solu- 

 tion and then to prevent the formation of nascent hydrogen at the surface 

 of the zinc by connecting the latter by wire to a piece of platinum placed 

 in a different part of the solution and prevent diffusion of liydrogen by 

 surrounding the zinc with a porous cup. Tlie zinc was also made the 

 positive electrode from a weak battery. But local action around the zinc 

 produced a small amount of nascent hydrogen so that a slow reduction 

 always occurred. It is still hoped that this may be made successful. 



In this connection it is interesting to note that in order to eliminate 

 local action amalgamated zinc rods were tried. But in the presence of these 

 hydrogen caused a more rapid reduction of the dichromate than when they 

 were made the negative electrode from a battery. The reason for this has 

 not been determined and will be the subject of further inquiry. 



The reduction of hydrogen peroxide was attempted using the platinum 

 rosette as contact agent. No change in the amount of the peroxide could 

 be detected with the usual tests for that substance after hydrogen had 

 passed for four and one-half liours. But when the platinum was made the 



