260 ANALYSIS of a BLACK SAND 
The lofs will not appear exceflive, if we confider, that a por- 
tion of the arfenic muft have been fublimed, before the pre- 
fence of that metal was fufpected. 
Upon the whole, I think we may confider the fpecimen of 
iron-fand examined, as compofed of g parts protoxide of iron, 
and 1 of red oxide of titanium. The prefence of titanium in 
this ore had been already detected by Lampapius, though, as: 
I have not feen his analyfis, I cannot fay in what proportion. 
II. ISERINE. 
TuE colour of this ore is iron-black, with a fhade of brown. 
It confifts of fmall angular grains, rather larger than thole of 
the iron-fand, but very fimilar to them in their appearance. 
Their edges are blunt ; they are fmoother, and have a ftronger 
glimmering luftre than thofe of the iron-fand. Luftre femi- 
metallic, inclining to metallic. The fracture could not be di- 
ftinétly obferved, but it feemed to be conchoidal; at leaft no- 
thing refembling a foliated fra@ure could be perceived. Opake, 
femihard, brittle, eafily reduced to powder; colour of the - 
powder unaltered; fpecific gravity 4.491 *; fcarcely attract- 
ed by the magnet. B 
1. A HUNDRED grains of the powdered ore were mixed with 
fix times their weight of carbonate of foda, and expofed for two 
hours to a red heat, in a platinum crucible. The mafs obtain- 
ed being foftened with water, diffolved completely in muriatic 
acid. When the folution was concentrated, it aflumed the ap- 
pearance 
* Tr, as the following analyfis would lead us to expect, the {pecimen exami- 
ned was a mixture of four parts iferine, and one part quartz and felfpar, the fpe- 
cific gravity of pure iferine fhould be 4.964. 
