544 



Professor Dewar 



[June 11, 



of the results was confirmed by varying in some cases the method of 

 separating the gases. The carbonic acid was first removed from the 

 mixture by caustic potash, the carbonic oxide being then absorbed by 

 subchloride of copper, and the remainder of the gases exploded with 

 excess of oxygen. The carbonic acid formed was again removed by 

 caustic potash, and the excess of oxygen by alkaline pyrogallate, the 

 residue being taken as nitrogen. The relative quantities of marsh-gas 

 and hydrogen were calculated from the total diminution after explo- 

 sion, and the amount of carbonic acid formed : — 



It will be seen that the above numbers are quite confirmatory of 

 Wright's results, the carbonic acid in the three meteorites examined 

 being by far the largest constituent, while marsh-gas in considerable 

 quantity was found in all. The percentage of this latter gas is some- 

 what higher than that found by Wright in the stony meteorites he 

 examined, but this is probably due to the fact that a rather higher 

 temperature was employed by the lecturer to drive off the gases. 

 This supposition seems to be confirmed on considering the analysis 

 of the Pultusk meteorite ; for whereas Wright's abstracted gas only 

 reached 1 • 75 times the volume of the stone, the total quantity of gas 

 obtained by the lecturer was twice as much or equal to 3 • 54 times 

 its volume. 



It is therefore unquestionable that marsh-gas is given off on heating 

 these meteoric stones, but whether it exists as such occluded in the 

 material, or whether it is formed by some chemical decomposition of 

 some organic constituent of the mass, is by no means clear. 



Wright came to the conclusion " that the marsh-gas really existed 

 as such in the stony meteorites, as the temperature at which it was 

 driven off would be too low for its formation," at the same time he 

 thinks it quite possible that " at very much higher temperatures, in 

 the reaction by which the carbonic acid is broken up by the iron, a 

 portion of the carbon might combine with the hydrogen present to 

 form marsh-gas." 



Knowing the great absorptive power for gases possessed by porous 

 bodies generally, it was thought advisable to determine directly what 

 this absorptive power was in the case of these stony meteorites, 

 which are of such an eminently porous nature. 



