264 A. C. LANE — GEOLOGIC ACTIVITY OF THE EARTH's GASES. 



zones and the alteration of enclosed fragments.* These six lines of evi- 

 dence agree remarkably well, and point to compounds of hydrogen, 

 nitrogen, oxygen and carbon, probably variousl}^ associated according 

 to temperature and pressure as principals. Sulphur (sulphates of the 

 alkalis, H^S, et cetera) and chlorides, fluorides and boric salts seem also 

 to be important. At lower temperatures, instead of free hydrogen and 

 carbonic oxide, we seem to have steam and carbonic acid. 



Table I. — Analyses of occluded Gases. 



Analyses. 



1. 



2. 



o 

 O. 



4. 



5. 



6. 



7. 



8. 



9. 



H 



88.8 



10.5 



0.7 



77.0 

 22.9 



67.8 



30.8 



2.2 



83.3 



14.2 



2.5 



35.0 



7.0 



50.3 



7.7 



21.0 

 21.0 



58. 

 0. 



85.68 

 9.86 







38.98 

 25.94 



28.80 

 tO.28 



41.44 



N 



13.91 



CO 



CO., 



29.77 

 tl4.88 













Sum 



100.0 



60 

 100 



99.9 



45 



100 



100.8 



25 

 100 



100.0 



85 

 100 



100.0 



100.0 



100.0 



287 

 100 



100.0 



100.0 



Ratio of volume of 

 gas to that of ab- 

 sorbent 



263 

 100 





1. Gas from Bessemer steel before adding spiegel. F. C. G. Miiller : Iron, vol. xiii, 1879, p. 649. 



" after 



open-hearth steel, " " " " " " 



cupola pig-iron, " " " " " " 



horseshoe nails heated two hours i7i vacuo. Graham : Proc. Royal Soc, June 20, 1866. 



the same after heating two hours more. " 



meteoric iron of Lenorto. " 

 cinder. Bell : Manufacture of Iron and Steel, p. 173. 



Importance in Crystallization of plutonic Rocks. — Facts as to the impor- 

 tance of the part these gases play in the development of the plutonic 

 rocks have accumulated so rapidly lately that one hardly knows where 

 to begin or to stop. For one line of facts look at the minerals^ such as 

 hornblende, quartz, orthoclase and mica, which have been reproduced 

 mainly or only Avith the assistance of superheated water or a similar 

 medium. These minerals, which are the common constituents of plu- 

 tonic rocks, rarely if ever occur in volcanic rocks, except under circum- 

 stances that point to their being either earlier than the eruption or of 



* Geikie : Text-book of Geologj^ 189 5, p. GOG ; Lacroix : Neues Jahrbuch, 1892, vol. i, p. 67. 

 fWith SO2, etc. 



J For artificial minerals see Fouque and Levy, " Syntliese des Minei-aux, 1882, and that depart- 

 ment in the Neues Jahrbuch. 



