STATES OF THE GASES. 



45 



TABLE 32. 



As a precautionary measure, to avoid the introduction of any metallic 

 iron in the process of pulverization, the diabase was reduced to a powder 

 in an agate mortar. The brass sieve was not used. Hence this hydrogen 

 did not come from any action of the acid upon a metal introduced during 

 the manipulations. 



This powder, after remaining in a vacuum with an excess of sulphuric 

 acid for three days, was washed thoroughly on a Gooch filter until the last 

 traces of calcium sulphate had been removed. After drying for an hour 

 at 125, the powder was placed in the combustion-tube and heated to 

 redness. The sulphuric acid left more gas in the rock than the nitric. 



TABLE 33. 



From these experiments it would appear that acids remove the critical 

 gas-producing factors without liberating a notable amount of any gas 

 except carbon dioxide. Whether hydrogen may not pass into solution 

 with the iron, without being freed, is a question which naturally arises, 

 but the balance of chemical opinion is against this supposition. 



Professor Dewar digested celestial graphite in strong nitric acid for 

 several hours and, after washing and drying, found that with heat it gave 

 exactly the same amount of hydrogen as before treating with the acid. 

 This would suggest that, in the case of celestial graphite, the hydrogen 

 was not connected with iron, but existed in some very stable form. 1 



If all the hydrogen was produced by the reaction of water on ferrous 

 salts, it would seem as if the volume obtained should bear a direct relation 

 to the quantity of these two critical constituents present in the rock. 

 To throw light on this matter, two rocks of the same origin, but of different 

 chemical composition, presented the most favorable line of attack. An 

 intrusive andesite and a specimen of vein quartz derived from the mag- 



1 Dewar, Proc. Roy. Inst., vol. 11, p. 550. 



