METEORIC DUSTS, N.S.W. 253 



would certainly escape all our methods of analysis. (1882). 

 At a height of 200 kilometres it must exceed the oxygen 

 in the proportion of 170,000 to 1, that is to say, at that 

 height the atmosphere would practically contain no oxygen. 

 . . . Even if there are only minute quantities of free 

 hydrogen on the surface of the earth, it may be in prepon- 

 derating proportion in the upper regions. 



Tissandier has shown how by burning iron wire in 

 oxygen we may often obtain iron spherules of exactly the 

 same nature as those floating in our atmosphere. 



" I have obtained similar spherules by using an iron file 

 as one pole of a dynamo machine and passing the file over 

 a copper wire connected with the other pole. The sparks 

 consist chiefly of iron globules like those to which Tissan- 

 dier attributes a meteoric origin, there are also spongy 

 metallic masses, which present exactly the same appear- 

 ance as the metallic iron found in the Sahara desert. The 

 reason why they did not oxidize is no doubt due to the 

 fact that a layer which were oxidized used up the oxygen 

 in the neighbourhood of the few particles which escaped." 



In 1883 the above Committee reported that three speci- 

 mens of solid matter from snow and ice of the Himalayas 

 were collected and examined. One from the Gamukdori 

 Pass (lat. 35° 5', long. 74° 13') 13,400 ft., and two from the 

 Shokari Pass (lat. 35°, long. 74° 38') 14,700 ft. There is no 

 human habitation near either of these places. The residue 

 amounted to '1 gramme for the 25 cubic feet of snow boiled 

 down in each case. All three specimens contained (1) 

 spherical particles of magnetic oxide of iron, (2) small 

 particles of metallic iron. These probably are of meteoric 

 origin. 



From the foregoing evidence it is extremely probable 

 that, as suggested by Haidinger, Reichenbach and others, 

 at all times and in all parts of the world there is a constant 



