of Olivine, Peridot, Sfc. 367 



parated in the metallic residuum. The fonnation of olivine, on 

 the other hand, manifestly took place under the co-ao-encv of 

 water, and therefore under circumstances favourable to the 

 combination of this metallic oxide. Perhaps it is also hence 

 not improbable that the oxide of nickel was taken by the olivine 

 from the gangue, and it might therefore not be uninteresting to 

 examine the basalt and the basaltic tufa to ascertain the pre- 

 sence of nickel. The circumstance also, that oxide of nickel 

 likewise occurs in the chrysolite may, according to this, very 

 well accredit the conjecture that this mineral (whose true habi- 

 tat and peculiar appearance we are not yet acquainted with) 

 exists also in basalts, and by no means has a meteoric origin. 

 The analysis of two other fossils of the olivine kind, taken 

 from two more masses of meteoric iron, concludes this 

 treatise. 



One of these minerals is met with in a ramous mass of iron 

 very like that of Pallas, which was found at Otumpa in the pro- 

 vince of Chaco-Gualamba, in South America ; and a piece of 

 which the illustrious M. Von Struve of Hamburg was so kind 

 as to send to Professor Stromeyer for chemical examination. 

 The olivine of this iron is externally like that which was taken 

 from the Pallas iron as the most perfect specimen. Its specific 

 gravity is at 68° F. and barom. 29-429 in. = 3-3497. And in 

 its composition it also exacdy corresponds with the Pallas 

 olivine. In 100 parts of it are contained 



Silica 38-25 



Magnesia 49-68 



Protoxide of iron 11-75 



Oxide of manganese 0-11 



99-79 

 The second of these two minerals, said to have been found 

 in the district of Grimma in Saxony, is part of the meteoric 

 iron which is preserved at Gotha in the Ducal Cabinet, and 

 was about a hundred years since contained in the collection 

 of minerals purchased for the cabinet of the former Saxon 

 burgomaster of Schenberg, Yet by the permission of the 

 late duke, Professor Stromeyer obtained through the kindness 

 of the Chancellor Braun in Gotha many fragments of this 

 iron, and also two grammes of the olivine with them. 



This olivine externally is not materially different from diat 

 of the other masses of meteoi-ic iron. Its specific gravity is 

 however somewhat less, and is, at 72-5° F. and barom. 29-764 

 in. only = 3-2759. But in its constituents it wholly difiers from 

 botli the foregoing ones. 



According to two analyses of it, which corresponded very 

 well with one another in the chief points, there are contained 

 in 100 parts of this mineral Silica 



