Dr. Walter Flight — History of Meteorites. 403 



peridot or chrysolite, occurring in crystalline grains, and cemented 

 together with a white opaque silicate. Under the microscope the green 

 granules are seen to be tolerably symmetrical crystals, varying in 

 size from a small pin's head to microscopic dust ; they were found on 

 analysis to be a highly ferriferous enstatite or bronzite. They 

 crystallize in the prismatic system, and give the following results 

 of measurements, which accord closely with the numbers obtained by 

 Von Lang when examining the enstatite of the Breitenbach siderolite : 



Breitenbach enstatite. 



100, 110 = About 46° 45° 52' 



100,101 = 49° 4' 48° 49' 



110,110 = About 88° 88° 16' 



110,101 = 58° 39 58° 24' 



The specific gravity of the mineral is 3*198, the hardness 5-6, and 

 the chemical composition : 



Oxygen. 



Silicic acid 55-699 29-706 



Magnesia 22-799 9-119) 



Iron protoxide 20-541 4-564 j 14-059 



Lime 1-316 0-376) 



100-355 

 These numbers agree very closely with those required by the 

 formula (■§ Mg ^ Fe) Si0 3 , and show the mineral to be richer in iron 

 than the bronzite of the Breitenbach siderolite. A portion of the 

 meteorite was analysed in its entirety with the following results : 







Oxygen. 



Silicic acid 



53-629 



28-602 



Magnesia 



23-320 



9-328 ) 



Iron protoxide 



2Q--476 



4-550 J 14-305 



Lime 



1-495 



0-427 ) 



Chromite 



1-029 





99-949 

 These per-centages differ to so small an extent from those yielded 

 by the analysis of the picked crystals, that we arrive at the con- 

 clusion that both ingredients have the same composition, and find in 

 the Manegaum stone an instance of a meteoric rock consisting of a 

 single silicate. The Ibbenbiihren meteorite (1870, June 17th) has 

 since been shown by Vom Eath (see page 71) to be similarly con- 

 stituted. A very minute amount of meteoric iron, far too small for 

 isolation and analysis, occurs in the Manegaum stone. 



Found 1846. — Tula, Netschaevo, Russia. 1 



This remarkable mass of iron, which encloses a number of angular 

 fragments of rocky material and resembles a true breccia, was stated 

 by Auerbach to contain but little nickel. Bammelsberg now finds as 

 the result of two analyses, conducted according to different methods, 

 that the per-centage of this metal (and cobalt) is 10-24 and 9-84, or 

 about four times the amount detected by the earlier observer. 



1 C. Eammelsberg. Monatsber. Ah. Wiss. Berlin, 1870, lxx. 444. 



