1818.] Scientific Intelligence. 229 



zinc which is oxidated is also dissolved by the acid which is 

 liberated, and there is formed a mixed solution of nitrate of zinc 

 and of silver. 



The .nascent hydrogen from the negative pole reduces the 

 silver and the zinc at the same time. The zinc plate is covered 

 with a flocculent mass, of a blackish colour, which is in the state 

 of an hydrate ; the flocculent surface gradually becomes grey 

 and brilliant : this appears to be an alloy of silver and zinc in the 

 form of an hydrate. 



In the same manner when a plate of zinc is suspended in a 

 solution of the acetate of lead, the arborization with brilliant 

 facets which is produced is an alloy of lead and zinc, not, as was 

 formerly supposed, pure lead. An alloy of zinc and copper is 

 formed, when we place a plate of zinc in a solution of the acetate 

 of copper. In this case a blackish matter is produced, consist- 

 ing of zinc and copper, which, by means of the burnisher, may 

 be made to assume a very beautiful polish of the colour of gold. 



What is called the arbor Dianse is a solid amalgam of mercury 

 and silver ; if we add to the solution of silver and mercury gene- 

 rally employed in the above experiment some nitrate of copper, 

 we obtain large, brilliant crystals of silver, mercury, and copper. 



V. Chemical Researches on the Pellitory of Spain. By M. Gau- 

 tier, Apothecary in Paris.* 



The most remarkable quality of the pellitory of Spain, the 

 Anthemis Pyrethrum, is the acrid, burning sensation which it 

 produces upon the mouth when it is chewed, and the profuse 

 salivation which it excites. A quantity of the pulverized root 

 was successively acted upon by sulphuric ether, boiling alcohol, 

 cold water, and afterwards by boiling water, the products of 

 each step of the process being accurately examined. The 

 general results are, that the acrid property of the pyrethrum 

 depends upon an oil, which exists only in the bark, and which, 

 by a close inspection of the part, may be seen lodged in minute 

 vesicles. The author calls this a fixed oil, and says that it 

 possesses the following properties; it has a reddish colour, a 

 powerful odour, is insoluble in water, lighter than this fluid, 

 becoming concrete by cooling, and melting again by heat ; it 

 forme a saponaceous compound with the alkalies, the soaps being 

 M'luble in water and in alcohol. Besides this fat or fixed oil, 

 M. Gautier mentions a volatile oil as one of the constituents of 

 the pyrethrum ; we are rather disposed to think that this is the 

 immediate cause of the acrid properties, and that the effects of 

 the fixed oil depend upon its being combined with a portion of 

 the volatile oil. It also contains a yellow colouring matter, 

 which appears to be of the nature of a gum-resin, and a sub- 

 stance resembling a gum, which, however, is principally charac- 

 terized by its negative properties. 



• Abridged from Journ. Fliarm. iv. 49. (Feb. 1818.) 



