450 Dr. Walter Flight— On Meteorites. 



The iron sulphide, regarded as troilite, when in the form of pieces, 

 is not acted upon by the magnet, and when in the form of powder, 

 but feebly so. The ratios of iron to sulphur in troilite or iron mono- 

 sulphide, and in magnetic pyrites, differ in so small a degree that 

 the analytical results do not always put the question at rest. It is 

 moreover a question whether the meteoric sulphide, associated as it 

 is with nickel-iron, does not actually contain some of the metal as 

 an ingredient. The numbers obtained in these analyses are as 

 follow : — 





Calculated 





Found 









I. 



II. 



III. 



Iron 



... 63-63 



65-87 



63-58 



63-00 



Nickel ... 



— 



1-40 



— 



1-02 



Sulphur 



... 36-37 



34-27 



36-42 



35-27 



Silicic acid 



— 



— 



— 



0-67 



100-00 101-54 100-00 99-96 



The asmanite appears to have the density of 2-274:-2-278, and the 

 following composition : — 



SiO^ FeaOg CaO and MgO. Loss on Ignition. 

 95-771 3-16 Trace 1-07 = 100-00 



97-84 1-65 „ 1-01 = 100-50 



As regards the crystalline form of this mineral, Weisbach considers 

 that the recent researches of Schuster and of Von Lasaulx have 

 placed almost beyond any doubt the identity of tridymite and asma- 

 nite. It occurred to the author that the relative solubility of tridy- 

 mite and asmanite in potash solution should be determined, and in 

 as nearly parallel experiments as it was possible to devise, it was 

 found that of tridymite from Siebenbiirgen 49*63 parts, and of asma- 

 nite from Eittersgriin 43-88 parts, were dissolved. 



The bronzite, the most prominent of the non-metallic minerals, 

 was obtained in a pure form with comparative ease. It is but 

 slightly affected by the blowpipe, and is not acted upon by acids 

 with the exception of hydrogen fluoride. Its specific gravity is 3-310. 

 It possesses the following composition : — 



I. 



Silicic acid 57-27 



Alumina 2-28 



Iron protoxide ... 10-99 



Manganese protoxide 0-41 



Magnesia 24-78 



Lime 1-77 



Soda not determined 



Chromite 0-94 



98-44 99-83 98-90 



No trace of olivine was met with in this material. 

 Heated in vacuo the substance of the meteorite lost 0-23 per cent. 

 of its weight, and the gas evolved took fire, but was so small in 

 quantity that it could not be further examined. The meteorite 

 possesses the " crust of fusion " in a fully developed form ; it is of 

 about the same thickness as a sheet of paper, and close under it are 



1 By difference. 



II. 



III. 



56-56 



56-56 



2-05 



2-04 



10-74 



10-09 



0-42 



0-55 



25-13 



25-59 



2-52 



1-66 



1-43 



1-43 



0-98 



0-98 



