260- ANALTSIS of a BLACK SAND 



The lofs will not appear exceffive, if vye confider, that a por- 

 tion of the arfenic mufl 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 9 parts protoxide of iron, 

 and 1 of red oxide of titanium. The prefence of titanium in 

 this ore had been already detected by Lampadius, though, as 

 I have not feen his analyfis, I cannot fay in what proportion.- 



II. ISERINE. 



The colour of this ore is iron-black, with a made of brown. 

 It confifts of fmall angular grains, rather larger than thofe of 

 the iron-fand, but very fimilar to them in their appearance. 

 Their edges are blunt ; they are fmoother, and have a flronger 

 glimmering luftre than thofe of the iron-fand. Luftre femi- 

 metallic, inclining to metallic. The fracture could not be di- 

 ftinctly obferved, but it feemed to be conchoidal ; at leaft no- 

 thing refembling a foliated fracture could be perceived. Opake, 

 femihard, brittle, eafily reduced to powder ; colour of the 

 powder unaltered j fpecific gravity 4.491 *> fcarcely attract- 

 ed by the magnet. 



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, duTolved completely in muriatic 

 acid. When the folution was concentrated, it aflumed the ap- 

 pearance 



* If, as the following analyfis would lead us to expedt, the fpecimen 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. 



