EVOLUTION OP OASES FROM HOMOGENEOUS LIQUIDS. 



267 



Thus, on introduction of the graphite the interval required for the evolution of 

 10 c.c. of gas is suddenly reduced from 9'"88 to 1''37, notwithstanding the loss of mass 

 due to a tumultuous effervescence of gas. 



Effect of Barium Sulphate. 



Some barium sulphate was prepared by precipitation of the chloride with sulphuric 

 acid, and washed carefully from all traces of chloride ; it was then ignited in the usual 

 manner. 



Temperature 37-G-38 0> 0. 



The interval of time is here reduced from 30' to 5' by the presence of the precipi- 

 tated barium sulphate. 



Decomposition of Ammonium Nitrite in Aqueous Solution into Nitrogen and Water. 



NH^NOj = N 8 + OH,. 



The preparation of nitrogen gas by heating together concentrated aqueous solutions 

 of potassium nitrite and ammonium chloride is well known. The effect of finely 

 divided particles in promoting the evolution of nitrogen was studied as affording an 

 example of a case in which there is formed a gas, most sparingly soluble, and thus 

 not likely to be stored in any quantity in the solution of the salts undergoing decom- 

 position. 



Effect of Silica. 



A mixture was made of 40 c.c. of a concentrated solution of potassium nitrite and 

 120 c.c. of a cold saturated solution of ammonium chloride, containing about 33 per 

 cent, of the salt. 



Variation of temperature, 57 0f 7-57'9. 



2 M 2 



