106 Scientific Intelligence. 
B. Those which contain sesquioxyd of iron but no alumina. Acmite, 
aegirine and babingtonite belong to the augite type, arfvedsonite to the 
hornblende type. 
hose which contain sesquioxyd of iron and Gumins, These are 
the aluminous augites and hornblendes, 
ose which contain alumina bs no sesquioxyd of iron. Spodu- 
mene of the augite type is the only m 
e assumption of a larger iaitity of oxygen in the hornblendes 
or of the existence of a bisilicate in them rests only in the imperfections 
of former analyses. The aluminous augites and hornblendes contain prot- - 
oxyd and sesquioxyd of iron, the latter m addition a considerable quan- 
tity of alkalies. 
Se co att ae atet iron is everywhere present as a base and its bisili- 
cate i th the bisilicate of protoxyd of iron and other 
Mebissnpibe: 
(6.) The aluminous augites and hornblendes have an analogous consti- 
rege’ Smee is at the same time that of all the other members, only in 
umina is an — constituent.—Pogg. Ann., cili, 
213 3, pe 
2. Re 
sulphid of iron ad id exhibiting 3 in some respects a remarkable analogy to 
nitroprussids of Playfair. When a solution of a per-salt of iron is 
added drop by drop to a mixture of solutions of an al ne nitrite — 
minous black precipitate is thrown down which on boing diolvas 
almost completely. ‘The filtered igi deposits black crystals which are 
oblique rhombic prisms. They are soluble in boiling water, alcohol, 
woodspirit and ether. Five centigrams communicate to one litre of water 
the color of brandy. Their taste is styptic and afterwards bitter. The 
