2it - Htjory and Attaints of the Siberian Red Lead. 



cefiary for exarmnacion. Thefe fmall cryflals arc found on the fand-ftone as wetl as on tKe 

 quartz. 



" I can give no other detail refpe(3:ing thefe minerals, which will not fpeedily be ex- 

 haufted in this country, unlefs the veins fliould extend themfelves to a great depth." 



SECTION IL 



Account of the Experiments formerly made on the Siberian Red Lead. 

 THE beautiful red colour, tranfparency, and cryflalline figure, of the Siberian red lead 

 foon induced mineralogifts and chemifts to make enquiries into, its nature. The place 

 of its difcovery, its fpecific gravity, and the lead ore which accompanies it, produced an 

 immediate fufpicion of the prefence of that metal ; but, as lead had never been found in 

 poflclTion of the charadleriftic properties of this Siberian ore, they thought, withjuftice, 

 that it was mineralized by fome other fubftance ; and Lehman, who fivft fubjefted it to 

 chemical analyfis, aflerted, in a Latin differtation printed at Peterfburgh in 1766 (I fup- 

 pofe 1786), that the mineralifers were arfenic and fulphur. 



In 1789 Citizen Maquart undertook a. long courfe of experiments, in which I had the 

 advantage to participate, as he has been pleafed to mention in -the introduftion to his work 

 entitled EJfais de Mineralogie du Nord. The objeft of thefe experiments was to determine 

 the nature of the mineralifer of red lead. We fought in vain for the prefence of arfenic; 

 but, by an error, arifing from the ftatc of chemical knowledge at that time, we con- 

 sidered the red lead ore as a combination of fuper-oxygenated lead, iron and alumine. 



Since that time Bindheim affirmed, that he had found it to contain molybdic acid, iron, 

 flickel, cobalt, and copper. 



From the confideration of thefe refults, fo diametrically oppofite to each other, and under 

 the encouraging confideration of the immenfe progrefs of chemical fcience fincc the reno- 

 vation of its language and the re£lification of its theory, and venturing likewife to place 

 fome dependance on the flight experience I have acquired in the art of eflaying fince I had 

 the advantage of belonging to the eftablifhment of mines, I thought proper to fubmit this 

 fubllance to a new examination. My labours have not been without their recompcnfe ; 

 and I hope to prove, in the following paragraphs, that all which has hitherto been aflerted 

 with regard to the mineralifer of the Siberian red lead is entirely deftitute of foundation ; 

 that it contains neither arfenic, as Lehman pretended ; nor the molybdic acid, and the three 

 or four metals, announced by Bindheim; nor iron nor clay, as Maquart and myfelf ima- 

 gined ; but a new metal, poflbffing properties entirely unlike thofe of any other metal. 



SECTION m. 



The new Methods of Analyfis applied to the Red Lead of Siberia. 

 THE fcience of chemiftry is at prefent founded upon principles fo certain, that, when tlie 

 operator has reafon to form a prefumption refpe<Sting the nature of a compound body, it is 

 poihble tadifcover, by mere indu6lion, the rneans which are mod likely to feparate its ele- 

 ments. Thus, from the fufpicion that an acid might exift in the compofition of the red 

 Jead, I concluded that 1 might dccompofe it in the way of double affinity ; and the rcfult 

 of my experiments -con-firms the indications of theory. ' 



The 



