A. W. Wright— Oases contained in Meteorites. 255 



iron, with a deposition of pulverulent carbon, though the 

 action is very slight at temperatures less than 400° C. The 

 commission who reported upon his memoir, in repeating some 

 of his experiments, found that the temperature must exceed 

 350° in order that this effect may be produced at all. At 

 higher temperatures the action is very marked. More recently 

 Sir I. Lowthian Bell, in his work containing the results of a 

 very elaborate and admirable seiies of researches upon the 

 mutual action of the two oxides of carbon in the presence of 

 metallic iron and oxide of iron,* has, in the main, confirmed 

 Griiner's conclusions, but has shown that the results vary, not 

 only with the temperatures, but also with the relative propor- 

 tion of these substances present. He found that pure carbonic 

 oxide begins to reduce Fe^Og at from 140= to 200° C, 

 according to the substance used, while at a moderate red 

 heat the oxygen is rapidly removed, with the formation of 

 carboi) di-oxide. On the otber hand the latter gas was 

 partially reduced by spongy iron at a low red heat, with 

 the formation of carbonic oxide. We have further to consider 

 the action of the hygroscopic moisture upon the metallic iron, 

 as well as the mutual action of hydrogen and oxide of iron, at 

 elevated temperatures. 



It is very evident then that the composition of the gases 

 obtained at or above the temperature of red heat cannot be con- 

 sidered to represent accurately the true constitution of the 

 gaseous contents of a meteorite, and especially is this true in 

 the case of the stony ones. On the other hand we can hardly 

 assert with confidence that the different gases are expelled in 

 exactly their proportionate amounts at all temperatures. In 

 fact the experiments show that the proportions of the gases 

 vary with the temperatures of their evolution in a manner not 

 satisfactorily explainable on the assumption that such an effect 

 is due to chemical action alone. It is important therefore that 

 the experiments should be conducted in such a way as to facil- 

 itate as much as possible the evolution of the gases, while at 

 the same time they are exposed for as short time as possible to 

 the action of high temperatures. The first of these conditions 

 IS attained in a good degree by reducing the material examined 

 to a state of minute subdivision. The second is approximated 

 V continuing the application of the high temperatures for the 

 shortest time consistent with a satisfactory effect in driving off 

 the gases sought. 



In the case of the iron meteorites the material was generally 

 prepared by boring out the solid iron with a steel drill upon a 

 lathe, the substance being rendered as fine as possible. In 



