254 A. W. Wright— Gases contained in Meteorites. 



"hitherto examined," provided the Iowa meteorite could '"be 

 taken as a representative of its class."* With a view to ob- 

 tain data for a more extended comparison, the investigation 

 was continued, and a number of meteorites of both classes 

 examined. The results of this work are given below, and it 

 will be seen that thej tend to justify completely the conclu- 

 sions in my former paper, so far as any limited number of 

 determinations could do so. 



The method of experiment was the same as that described in 

 the former paper, except in some of the minor details, and 

 need be but briefly described here. The specimen to be ex- 

 amined was placed in a tube of very hard and refractory glass, 

 which was merely softened at a red heat, and which, when 

 filled with the meteoritic substance, could be maintained for a 

 long time at this temperature without yielding more than so 

 much as merely to deform the tube In no instance was air 

 admitted by the cracking or drawing in of the hot glass. The 

 air was ex hausted and the gas collected by means of a Sprengel 

 pump of such perfection that it would produce a vacuum of 

 but a fraction of a millimeter, and maintain it for days un- 

 changed. The specimen tube having been attached to the 

 pump, the latter was set in action and kept running until the 

 air was thoroughly removed, as could be seen by the state of 

 the gauge. The meteorite was then heated cautiously and the 

 gas pumped out into the tube in which it was to be examined. 

 Further details of the mode of procedure, where varied in the 

 dilFerent cases, will be given in their appropriate places. 



The problem of determining the exact nature and relative 

 proportion of the gases in a meteorite is less simple than it 

 might at first sight appear. For not only, as Griiner has shown,! 

 is metallic iron attacked by carbon di-oxide, but it also, in the 

 presence of this gas, or other oxidizing agents, determines the re- 

 duction of carbonic oxide, and its disappearance therefore from 

 the gaseous products. In the case of the stony meteorites the 

 question is still more complicated, as there is always present a 

 greater or less quantity of oxide of iron, which at an elevated 

 temperature must exert no inconsiderable influence upon the 

 constitution of the gaseous mixture obtained from the mass. 

 Gruner's very careful experiments showed that pure carbonic 

 oxide progressively reduces the oxide of iron, at a temperature 

 of 400^^ C. On the other hand it is itself reduced by metallic 



