in the Red Lead of Siberia, 36^ 



Exp. IV. Reduction of the Oxyde of the Red Lead. 

 An experiment which could not but excite my curiofity 

 was, to know whether the acid of the red lead, treated in a 

 fuitabk manner, could be reduced to a metallic Mate. For 

 this purpofe I put 72 parts of this acid, extracted by the 

 muriatic acid in the manner before mentioned, into a cruci- 

 ble of charcoal, which I placed in another crucible of earth 

 filled with charcoal drift. Having then heated it for half an 

 hour in a force fire, I found in the charcoal crucible a me- 

 tallic mafs of a whitiih grey colour, in the form of needles 

 interwoven through each other, and which weighed 24 parts. 

 The refult of this operation ihews that the acid of the red 

 lead contains a large quantity of oxygen, fince of 72 parts 

 employed, 24 only, which make one third, were convene.' 

 into metal. 



Exp. V. Properties of the Metal. 



The (mail mattes with which I was obliged to make my 

 experiments did not allow me to difcover a great number of 

 properties in this metal. The few, however, which I ob- 

 ferved are fufneient to characterife it, and to induce me to 

 alfign it a particular place among the metallic fubftances. 



1. It is white, grey ifli, exceedingly brittle, infufible, fixed 

 and cryfiallifed into needles. 



2. Expofed to the heat of the blow-pipe it becomes covered 

 with a lilac-coloured cruft, which, on cooling, turns green. 



3. Heated by the fame apparatus with borax it does not 

 melt; but a part after being oxydated dhTolves in that fait, 

 and communicates to it a very beautiful green colour. 



4. The action of acids upon it is exceedingly weak. The 

 nitric acid \?. the only one which makes it undergo any re- 

 markable change. By diftilling five or fix times fucceffivclv 

 to drynefs 20 parts of this acid, concentrated, upon one of 

 the metal, I was able to convert it into an orange yellow 

 powder, which at firft was green. 



Thb 



