Chemistry and Physics. 111 
II, CHEMISTRY AND PHYSICS. 
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culiar oxychlorid, probably Nb, Cl,0,. The hyponiobic acid of Rose 
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Lear] 
alent of niobium is about 40. ‘The native tantalates and niobates may 
be included under the general formula 2RO,5R, O3, and there are vari- 
ous mixed or intermediate minerals between the true tantalite of Kimito, 
served that atoms and not equivalents are used: 
Potassium compounds, TiK,F,-H.0 NbK,F,0,H,0 WK,F,0,,H,0. 
Copper compounds,  TiCuF,.4H,0 TiCuF,0,4H,O WCuF,0,,4H,0. 
'b20,Cl, a better with Rose’s analyses than that given by Rose 
himself, Nb,Cl,. The author promises a further investigation of the 
Subject. 
. Hermann has published a very extensive and elaborate m smoir on the 
tantalum metals. He admits the existence of three distinct metals, 
namely: tantalum, niobium and ilmenium. Tantalic and iene 
Presented by the : | OF aan ae 
columbite of Middletown contains both ilmenic and hypo-niobic acids ; 
fo ermann’s methods of separating the different acids from each other 
We must refer to the original memoir. According to him the equivalent 
of ilmenium is 52°37, and that of niobium 52°80, a degree of coinci- 
