312 Tha Shalka Meteorite. [No. 4. 



With borax on platinum wire, a minute fragment fused partially 

 but very slowly. The glass was coloured of a pale green. 



When nitrate of potash is added to the bead of borax, it fuses quick- 

 ly and entirely to a pale grass green. 



A portion of the crust, in powder, fused in a crucible with nitrate of 

 potash gave only a pure wnite mass, wlrch, dissolved in water leaves a 

 dull red sediment and this by so^tion in muriatic acid is found to be 

 iron with a little silex. No traces of chromium could be detected in 

 these minute assays, but it would doubtless be found where the black 

 grains appear fused into the crust. 



By a careful examination the complete absence of nickel, cobalt, and 

 magnesia were established, and the results per cent, were as follows : — 



Water, 0. 12. 



Arsenic, trace. 



Sulphur, 0. 10. 



Iron peroxide, 26. 80. protox 24.48. 



Silica, 68. 60. 



Alumina, 0. 50. 



Oxide of Chrome, 2. 00. 



98. 12. 

 Loss, .... 88. 



100. 00. 



The black grains are chromate or sub-chromate of iron, and hence 

 a variable portion of the assay, depending on the quantity of these and 

 probably of that of the darker portion of the Aerolite, will be always 

 in the state of chromate of iron ; and the excessive friability of the mass 

 is explained by the absence of alumina and the earthy state of the silica. 



Reviewing this paper : Every lover of science will join with me in 

 repeating our obligations to Mr. Mactier for his active zeal in procur- 

 ing for us this valuable specimen, and in regretting deeply that we have 

 been unable to secure the entire stone, or at all events a good sectional 

 fragment of it, by which we might have obtained some better insight 

 into its state of aggregation at the centre, and hence have ascertained if 

 it had any nucleus ; and I cannot close without earnestly impressing 



