44G Miscellaneous Intellig:ence 



6' 



Earthy and metallic pinates may be procured pure, by dissolving 

 the precipitates from double decomposition in ether, and precipi- 

 tating" them by alcohol of 60 per cent. : or by boiling the earthy or 

 metallic neutral salts with an excess of pinate of potash ; or preci- 

 pitating such salts as are soluble in alcohol by an alcoholic solution 

 of pinic acid. 



The pinate of magnesia is white, pulverulent, agglomerating in 

 boiling water, dissolving readily in ether, acting with alcohol as 

 pinate of copper. The pinates of baryta, alumina, manganese, and 

 zinc are insoluble in alcohol, very soluble in ether, and resemble 

 earthy bodies. Pinate of lead is very little soluble in ether ; is a 

 white powder, which may be fused without decomposition, and is 

 then resinous and transparent. Pinate of copper is of a transparent 

 green colour, very little soluble in absolute alcohol, readily soluble 

 in ether and oils ; at a moderate heat it softens, at a higher tem- 

 perature becomes a proto-pinate. The other metallic pinates have 

 been formed and have similar properties. According to M. Unver- 

 dorben, the pinic acid should be placed immediately after the 

 benzoic acid. 



The Silvic acid is another substance described in this memoir. 

 It occurs in the resins of the pinus sylvestris and fir tree, and is pro- 

 bably identical with the crystalline substance found by M. Riess in 

 white pitch. It is separated by acting upon the resin several 

 times with alcohol, which takes up every thing but the sylvic acid. 

 The latter crystallizes almost entirely upon cooling, is colourless, 

 and requires a higher temperature than 212° for its fusion ; it does 

 not then crystallize upon cooling, but forms a clear transparent 

 mass. Once crystallized, the sylvic acid dissolves with difficulty in 

 cold alcohol of 65 per cent. If boiling, one third of its weight is 

 taken up. Absolute alcohol and ether dissolve larger proportions ; 

 though, when cold, not more than one third of their weight. By 

 this feeble solubility the acid may be distinguished from most resins. 

 The crystals appear as quadrangular prisms. The acid dissolves, 

 in all proportions, in volatile oils. The alcoholic solution strongly 

 reddens tincture of litmus. 



The sylvates are formed in the same manner as the pinates, and 

 have very nearly the same properties. Besides the neutral com- 

 pounds, a few acid sylvates may be formed ; as for instance, with 

 potash and soda. The sylvate of copper is soluble in absolute 

 alcohol, and may in that way be separated from the pinate of the 

 same base. — Bull. Univ. A. x. 161. 



§ III. Natural History, &c. 



1. Mineral or Native Naphthaline. — Many specimens of a mineral 

 substance, first found in 1822, have been presented to the Helvetic 

 Society of Sciences by M. Koenlein. It was discovered in the coal 

 formation of Uznach, and has a great analogy to Naphthahne. Its 

 primitive form is an irregular octoedron, not yet measured, but 



