48 THE GASES IN ROCKS. 



Though as transparent as window-glass, one volume of this beryl con- 

 tributed 0.31 volume of hydrogen. A determination of its accessible iron 

 was made by pursuing the same method as was used for the quartz. The 

 results were: 



35.00 gms. beryl contained 0.0003 gm. Fe 2 O 3 



127.52 gms. beryl would contain 00109 gm. Fe 2 O 3 



127.52 gms. beryl would contain 00076 gm. Fe 



Fe (as FeO) required to give 1 c.c. hydrogen 00748 gm. 



Maximum amount hydrogen from reaction O.lOc.c. 



Hydrogen actually obtained (0 and 760 mm.) 14.89 c.c. 



Hydrogen not from this reaction 14.79 c.c. 



This beryl expelled nearly 150 times as much hydrogen as can be 

 assigned to the interaction of steam and ferrous oxide under the most 

 generous assumptions. The actual hydrogen is 37 times the maximum 

 quantity possible from this weight of iron, either as pyrite or in the metallic 

 state. Here is a very declared case demonstrating the inadequacy of chem- 

 ical reactions involving iron to generate the hydrogen obtained. 



Heated in a closed tube with a limited amount of air, beryl is known 

 to give up a small quantity of water which, in some varieties of the mineral, 

 may reach 2 per cent. The question whether the excess of hydrogen over 

 that possible from reactions between water and iron could have arisen 

 from the dissociation of this water is easily answered. The recent researches 

 of Nernst upon the dissociation of steam indicate that, at temperatures 

 below 2000 C., the process takes place only to a very limited extent. 

 At 1124 C., which is somew r hat above the point to which the beryl was 

 heated, only 0.0078 per cent of the total steam can be dissociated. 1 At 

 this temperature, 127 grams of beryl containing 2 per cent of water should, 

 on the basis of Nernst's figures, yield 0.24 cubic centimeter of hydrogen, 

 provided the gas was quickly cooled. Hence only a small portion of the 

 hydrogen can be attributed to the dissociation of water present in the 

 mineral. 



To the question of the importance of ferrous salts in the production of 

 hydrogen, it is possible that meteorites, which have usually been regarded 

 as free from water, can add testimony of some value. Though it is true 

 that in freshly fallen specimens hydrous minerals have not yet been recog- 

 nized, 2 nevertheless, the researches of Graham, Mallet, Wright, and Dewar, 

 besides my analyses of the Allegan, Estacado, and Toluca meteorites, 

 have shown that these bodies, when heated, give off much gas, rich in 

 hydrogen. If these meteorites really contained no water, either original 

 or by absorption from the earth's atmosphere, the hydrogen obtained 

 from them can not be attributed to the decomposition of water; it must 

 have been held within the mass of each meteorite, either entrapped or 

 occluded. 3 But in several instances, at least, the investigators have stated 

 that a certain quantity of water was driven off, though perhaps this came 

 from weathered aerolites. The chemical analysis of the Allegan meteorite, 



1 Nernst, Chem. Central-Blatt, 1905, 2, p. 290. 



2 Farrington, Jour, of Geol., vol. 9 (1901), p. 532. 



3 It is to be remembered that a few meteorites have been found to contain hydro- 

 carbons, from which hydrogen might arise, but the presence of these hydrocarbons from 

 inorganic sources is more remarkable than that of hydrogen itself. 



