248 A. LIVERSIDGE. 



Iron sesquioxide 6*120 



Calcium carbonate 15*940 



Magnesium carbonate, traces of alumina, phos- 

 phates, etc 2*121 



Insoluble in hydrochloric acid 34*344 



100*010 



In further papers 2 M. Tissandier gives additional infor- 

 mation upon some specimens of atmospheric dust and 

 especially upon those which fell on the Canary Islands, 

 Feb. 7th, 1863, at Syracuse and in Italy on May 10th, 

 1872, and at Boulogne sur Mer, October 9th, 1876. 

 Drawings are given to show the differences between such 

 meteoric dust and the sands of the English channel and of 

 the desert of Sahara. In the same volume, p. 364, there 

 is also a note, by Mr. Phipson of London, upon the presence 

 of metallic iron in atmospheric dust. 



In an account of his expedition to Greenland in 1870, 

 Prof. A. B. Nordenskjold states 3 that at the bottom of the 

 holes in the ice he found a grey powder, to which he gave 

 the name of cryoconite (Kpyos ice and k6v is dust); he found it 

 on inland ice as well as on the shore ice ; Nordenskjold 

 concluded that it was not derived from the disintegration of 

 the rocks in the district but from meteoric sources, especially 

 as it contains particles of metallic iron bearing cobalt, 

 copper and probably nickel. Prof. Nordenskjold describes 

 it as occurring in layers some millimetres thick and often 

 conglomerated into small loose balls, and under the micro- 

 scope as being principally made up of white angular trans- 

 parent particles intermixed with vegetable fragments as 

 well as particles of what appears to be felspar and augite. 



Dr. G. Lindstrom obtained the following analytical results 

 from a sample : — 



1 Comptes rendus, lxxxiii., p. 821. 2 Ibid., lxxxiii., 3 876, pp. 76, 1184. 

 3 Geological Magazine, 1872, p. 355. 



