552 Prof. Dewar on Becent Researches on Meteorites. [June 11, 



What is the origin of the gases in meteorites? Their presence 

 agrees with the discovery of Dr. Huggins, that comets give a hydro- 

 carbon spectrum. The origin of terrestrial graphite is far from 

 being agreed upon by geologists ; in some places it is evidently 

 transformed coal, in other cases they cannot say whether it comes 

 from vegetable or primitive sources. Whatever the origin of the 

 graphite in meteorites, it contains similar impurities to those in 

 terrestrial graphite ; the nodules in celestial graphite are similar to 

 those of terrestrial graphite, and might as well have come from 

 some body like the earth as from any other source. Another con- 

 clusion is that the marsh-gas is not occluded in meteorites, but is a 

 product of distillation by heat, just as the gas might be distilled from 

 shales. The graphite of meteorites has no power of occluding marsh- 

 gas, therefore the inference is that the marsh-gas and hydrogen in 

 them are the result of the decomposition of organic bodies. In the 

 spectrum of one of the comets. Dr. Huggins once photographed a 

 peculiar band in the ultra-violet, which band indicated the presence 

 of cyanogen. One meteorite on the table contained chloride of 

 ammonium, therefore it contained a compound of nitrogen, and such 

 would account for the production of cyanogen. 



[J. D.] 



