IT S PROPERTIES AND COMPOSITION MUNRO 



19 



Blue were made by dissolving equal quantities in equal volumes 

 of water and of alcohol. These solutions were placed in tubes 

 over agar. The tubes were connected in parallel. It was found 

 that the migration of hydrosol was greater than that of the alco- 

 sol. Results were of little value, however, on account of the 

 unequal diameter of the tubes. Since resistance, and therefore 

 amount current varies with the area of cross section, and rate 

 of migration depends on amount of current, the difference 

 might have been partly due to difference in tubes. The resis- 

 tance of the solutions was so great that the current could not 

 be measured with mil-ammeter. 



Analysis of Blue. — Samples of "hydrogel" were pul- 

 verised and dried at temperature of 105°-110°C until three 

 weighings, taken at intervals of one hour, gave the same weight. 



Apparatus. — Apparatus for reduction of an oxide was 

 set up. It consisted of a hydrogen generator; wash bottle 

 containing C. P. sulphuric acid; short length of hard glass tub- 

 ing, small platinum boat and a U-tube containing sulphuric 

 acid over glass beads. The platinum boat, which had been 

 ignited, cooled in a desiccator and weighed, was partially filled 



with the prepar- 

 ed Blue. The 

 amount of Blue 

 taken for ana- 

 lysis was re- 

 corded. The 

 boat and Blue 

 were placed in 

 the hard glass 

 tub&, the appar- 

 atus connected. 

 When a stream 

 of hydrogen had 



been passing through the apparatus for ten minutes, 

 heat was applied to the boat. It was heated at red heat for 

 eight hours. The boat was weighed as quickly as possible and 



Fig. 7 



