THE CONSTITUENTS OF METEORITES 527 



brown in color and transparent when pure. Hardness 4, specific 

 gravity 2.58. It is isotropic and has equal cleavage in three 

 directions, hence is doubtless isometric. In the Bustee meteor- 

 ite it occurs in rounded grains, coated with gypsum through 

 alteration. 



Certain yellow grains found in the Bishopville meteorite were 

 also considered by Maskelyne to be this mineral. Aside from 

 these two occurrences it has not been positively identified in 

 any other meteorite. 



Calcium sulphide resembling oldhamite was obtained by 

 Maskelyne bv heating caustic lime in a glass tube, first with 

 h3'drogen, then with hydrogen sulphide. Vogt has noted a 

 similar compound formed in furnace slags. 



It has not been found as a terrestrial mineral. 



On dissolving the oldhamite of the Bustee meteorite, Maske- 

 lyne found a residue constituting about 0.3 per cent, of the 

 weight of the former, consisting of yellow octahedrons of micro- 

 scopic size. These were found to be unaffected by acids or 

 oxygen, while qualitative tests indicated sulphur, calcium, and 

 titanium or zirconium. Maskelyne regarded the mineral there- 

 fore an oxysulphide of calcium and titanium and gave it the 

 name osbornite. No other occurrence of the mineral is known. 



Hydrocarbons. — The hydrocarbons found in meteorites may be 

 divided, following Cohen, ^ into three classes : (<^) compounds of 

 carbon and hydrogen; (^) compounds of carbon, hydrogen and 

 sulphur ; and (<r) compounds of carbon, hydrogen and oxygen. 

 They especially characterize meteorites of the class known as 

 carbonaceous, which includes seven or eight distinct falls of mete- 

 orites of black color, low specific gravity and containing a sen- 

 sible amount of carbon. They have been obtained from some 

 other meteorites however, such as those of Collescipoli and Goal- 

 para. The hydrocarbons of the first class are obtained by treating 

 these meteorites with alcohol or ether. They are resinous or wax- 

 like bodies which completely volatilize on the application of heat. 

 When heated in a closed tube the resinous substances first fuse, 



^Meteoritenkunde. Heft. I, p. 159. . i.; .(■: ,; -i .:;/■;. ; 



