140 



(.'Iciiit'iits, liut i( is chiiiiit'd tliat it offers a better exiilanation for the varying 

 degrees of activity of liydrogen obtained from different sources and tlaat 

 it also explains the activity of liydrogen absorl)ed in metiils. 



The experiments described in this paper are designed to stndy the 

 activity of liydrogen from various sources as sliown in its action on 

 chromic acid and chromates as well as on hydrogen i)eroxide and perman- 

 ganates. These were chosen because they are not the most readily re- 

 duced or because their disappearance may be easily determined by color 

 reactions. Tlie attempt was made to study the effect of each of the sub- 

 stances which would need to be present for the reduction of the sul)stance 

 by nascent hydrogen. In the preparation of free hydrogen for use car(> was 

 taken to remove any foreign material wliicli might act as an oxidizing 

 or reducing agent. Very dilute solutions of the oxidizing agents were used 

 in order that a slight color claange might be the better noticed. The acid 

 was 30% C. P. sulphuric. Pure stick zinc was used, a dozen or more being 

 bound together so tliat the lower end of the pile was concave, tlius allow- 

 ing hydrogen to collect and work its way up between the sticks. The results 

 with potassium dichroinate solution \A'ere as follows : Purified hydrogen 

 passed into the aqueous or acidified solution caused only a very slight re- 

 duction in several hours of time. With zinc rods in the aqueous solution a 

 very slight reduction could be noticed at the end of eight hours passage of 

 the hydrogen. Nascent liydrogen generated in the solution caused a much 

 more rapid reducti<in of the chromate. 



Next a solution of cbroiuiuni ti'ioxide was ni;ide. the zinc rods wer(> sns- 

 licnded in the solution and especially imrilii-d hydrogen tanscd to pass 

 i;]> Jiround the bundle of rods several houi's a day until the time amounted 

 to 'jnr) liours. During the time the air was excluded and the spact^ above 

 the li(piid (the rods were oiil\ jiartly sulmicrged i was an atiiiosiiliere of 

 hydrogen. At the end of this time the solution was still distinctly xcllow 

 though slightly lighter in color (li;in at the conniiencenienl. 



The same kind of an I'xperiniciil was reiie.-ited willi potassium dichro- 

 inate but platinum foil was substituted for the zinc rods. In oi'dcr tliiil tlic 

 hydrogen might be divided into small bubliles and come into cout.ici with 

 as much iilatinum as was possible a jilatinnm lilti'ring cone was scnlcd into 

 the end of the delivei\v tulie and Just above this was fastened a rosette 

 made of strips of platinum foil. 'I'lie hydrogen i)ubbles Inuuped against this 

 foil as they rose through the liipiid. ('oiniection was made so that this plat- 

 inum might be made the ucg.-ilixc electrode Tor the pi'oductiou of nascent 



