254 ANALYSIS of a BLACK SAND 
rate. But after all that can be attracted by the magnet is re- 
moved, the greater part of the black powder ftill remains. This 
refidue is indeed attracted by a powerful magnet, but fo very 
feebly, that it is not poffible by means of it to feparate it from 
the grains of fand with which it is mixed. Thus we learn, that 
the black matter confifts of two diftiné fubftances; one of 
which is powerfully attracted by the magnet, the other not. 
As this fecond fubftance was obvioufly f{pecifically heavier-than 
the grains of fand with which it was mixed, I placed a quanti- 
ty of the powder on an inclined plane, and by expofing it cau- 
tioufly, and repeatedly, to a jet of water, I fucceeded in wafhing 
away moft of the grains of fand, and thus obtained it in a ftate 
of tolerable purity. 
Tue firft of thefe minerals we may call iron-sand, and the 
fecond iserine, as they belong to mineral fpecies which oryc- 
tognofts have diftinguifhed by thefe names. 
I, IRON-SAND... st uods 931 
THE iron-fand is much fmaller in quantity than the iferine, 
and does not exceed one-fourth of the mixture at moft. Its co- 
lour is iron-black. It is in very {mall angular grains, common- 
ly pretty fharp-edged, and fometimes having the fhape of im- 
perfect octahedrons. The furface is rough; the luftre is feebly 
glimmering and metallic; the fracture, from the fmallnefs of 
the grains, could not be accurately afcertained, but it feemed to 
be conchoidal. Opake, femihard, brittle, eafily reduced to pow- 
der. Powder has a greyifh-black colour; powerfully attrac- 
ted by the magnet ; fpecific gravity 4.765. 
1. As acids were not found to aé& upon this mineral, 100 
grains of it were reduced to a fine powder, mixed with twice 
its 
