1825.] Scientific Notices— Chemistry. gg| 



indebted to M. Mollerat for the observation, which be coraiqus 

 picated to me a short time since, on my visiting his fine mai)ii-» 

 factory for making vinegar from wood, in Burgundy. 



In a series of operations for preparing sulphate of copper by 

 calcining copper with sulphur, solutions of the sulphate are 

 obtained, which beoome turbid by the separation of an insoluble 

 subsulphate. They are placed in a tub, half buried in th§ 

 ground, in order to become clear. It is against the interior side^ 

 of this tub, and always at the junction of two staves that sraaU 

 buttons (champignons) of metallic copper are observed to form, 

 which gradually increase in size, and would doubtless ultimately 

 become considerable masses. 1 have some specimens which I 

 detached from the tub with a portion of the wood adhering to 

 them. 



On one side we find these bits of copper moulded on the 

 wood of the tub, whose striae are impressed on their surface ; oij 

 the other, they have the form of mammellse with very minute, 

 brilliant, crystalline facets. 



One of these specimens weighs more than 75 grammes 

 (nearly 2| oz. English). 



The chemical action by which the copper is revived is easily 

 explained. The protosulphate of copper which unquestionably 

 exists in the solution, in passing to the state of deutosulphate, 

 deposits its base which gives up its oxygen and acid to form the new 

 salt. It is evident that the revival of the copper may be effected 

 in this manner without the assistance of any iron, and in fact 

 there are no traces of that metal in the interior of the tub. It is 

 not, however, this part of the phenomenon that appears to me 

 most remarkable, but the cohesion, acquired by the copper so 

 precipitated from the midst of a solution ; a cohesion which is 

 so great as to allow the metal to be hammered in the cold and 

 reduced to thin leaves ; and whose specific gravity is equal to 

 that of fused copper, viz. 8-78. I have, moreover, filed a morsel 

 of this copper, and have produced a surface as brilliant and free 

 from pores, as could have been obtained by similar means with 

 an ingot of common copper. — (Annales de Chimie.) : 



2. Note on the Presence of Titanium in Mica. By M. Vauquelin. 



M. Vauquelin, at the request of Mr. Peschier of Geneva 

 (who conceived that he had fuund titanium in several micas in 

 such quantity as to be an essential constituent of the mineral), 

 repeated his experimeutis, first on two varieties of mica, and 

 afterwards on many others, in all of which he detected the pre- 

 sence of titanium, but in very minute quantity, and in different 

 proportions : the richest in titanium did not give more than ope 

 per cent, of that metal. 



, His tnode of analysis was as follows : — He ignited the mica 

 '(divided into thin lamina?, and cut very small with a pair of 



