Dr. Walter Flight — History of Meteorites. 123 



were readily flattened out ; the spherules, though so hard that a 



sharp steel file would scarcely touch them, were easily crushed. They 



had the following composition : 



Iron 



Nickel ... 

 Cobalt ... 

 Copper ... 

 Hydrogen 

 Carbon .. 

 Sulphur... 

 Chlorine 

 Magnetite 

 Silicic acid 



In the basalt of the ridge, of which an analysis is given under II. 

 in the same table, a compact, very brittle, yellow, or slightly brown 

 mineral occurs in thin flakes, sometimes in nodules of the size of 

 a pea; it is invariably penetrated and usually surrounded by 

 a mineral resembling hisingerite, to which attention will presently 

 be directed. The mineral has a hardness of 5 to 5-5, and easily 

 fuses before the blowpipe with evolution of sulphurous acid to a 

 magnetic regulus. It has the composition 



58-25 1 



Phosphoric acid trace. 



2-16 



Alumina 1'45 



0-30 



Nickel and Cobalt oxides 0-44 



0-13 



Magnesia 0-33 



0-28 



Lime 0-50 



1-64 



Soda 0-09 



0-16 



Potash trace. 



0-16 



Eesidue 6-07 



30-42 







0-26 



102-64 









Equivalent 









Eatios. 



Iron 



... 52-94 . 



. 57-91 . 



• 2-068 l 5-258 



. o-i9o ,r 258 



Nickel ... 



... 5-06 . 



. 5-53 . 



Copper ... 



... trace. . 



. trace. . 



— 



Sulphur ... 



... 33-41 . 



. 36-56 . 



. 2-285 



Silicate ... 



... 8-59 . 



— 



— 



100-00 100-00 



These numbers give the formula (Fe,Ni) S,or that of the iron (nickel) 

 monosulphide or troilite, which has hitherto only been met with in 

 meteorites. 



Intimately associated with the troilite, and evidently a product 

 of its oxidation and further alteration is the mineral already men- 

 tioned, the fresh fracture of which is of a light olive-green colour, 

 that by exposure to the air soon becomes brown, and after some 

 days turns quite black. 



Its specific gravity is 2-919, and composition : 



Silicic acid 



31-70 ... 



... 16-90 



Iron sesquioxide 



51-49 ... 



... 15-44 



Iron protoxide 



3-81 ... 



... 0-85 



Water 



... ... 15-56 ... 



... 12-05 



100-56 

 These numbers indicate the formula : 



FeO,Si0 3 +3(2Fe 2 3 -3Si0 2 )+14H 2 

 as that of the mineral. Nauckhoff, however, draws attention to the 

 rapidity with which the oxidation of the pulverized mineral takes 

 place : five days after the analysis was made the per-centage of iron 

 protoxide in another portion had fallen to 3*47, and after three weeks 

 to 1*55. The original unchanged mineral was probably a hydrated 

 ferrous silicate. 



{To be continued in our next Number.) 



