chemical Examinaflan cf (m anfient Speculum. 203 



mined ; hut the component parts which I foiuid are (jon^i- 

 iierably diflcixnt from those given by Roux ; who thinl<:s 

 that, besides cupper and lead, he discovered also antimony : 

 ■on the other hand, lie found no ginc. 



Professor ijtckman, in his liistQry of Inventions, considers 

 it very probable that antimany \vas known at that period, 

 and that it Avas employed in metallic compositions, lie 

 therefore requested the opinion of M. Gmelin on this sub- 

 ject, and the latter Informed him that it was not impro- 

 bable that the mass of the mttaliic mirror examined by Kovi.x 

 iiiight iiave contained antixuony : he was not, however, cour- 

 vinced that it contauied no tin. 



On the other hand, the results of my experiments ga\e 

 me, as the component parts of the antient mirror, copper, 

 tin, aivi lead. , 



The fragment subjected to analysis consistc/.! of a me- 

 tallic plate, both sides of wliich were covered with. a flat 

 stratum of verdigris, composed of tender fibres, . arranged 

 concentrically in a radiated form. The mass was compact, 

 very hard and brittle j on tlic fracture, \\'hen fresh, of a 

 grayish white colour, and by polishing acquired the beauti- 

 ful splendour of a mirror. The specilic gravity of the me- 

 tallic mass, when freed from the green rust, was to that of 

 distilled water as 8580 to iOOO. 



isl, A hundred grains of this mass, being put to. digest 

 with nitric acitl, gave a blue solutioo, and -after repeated 

 dijestiou left a whitish gray poivder, which -weighed 39 

 grains. 



2d, The nitric solution being evaporated to a. small 

 quantity w^ls subjected to proof with a saturated solution 

 of nmriate of soda, but no alteration was produced. The 

 mixture being then dccoiiiposed with sidphate of soda, it 

 became turbid and deposited a wliite heavy preoipitate, 

 which consisted of sulphate <jf lead. The whole quantity 

 at' it, when collected, was equal to 6 grains of metallic 

 lead. 



'I'he copper was then precipitated from the sohit,ion by 

 iron. The whole qujuitity of the metallic copper consisted 

 pf 62 graiiis. 



4th, Muriatic acid being poured over the 39 grains left 

 by the nitric acid, the whole was exposed to slow digestieni. 

 It gradually dissolved into a clear fluid of a straw-colour. 

 It was then dduled with three parts of water, and a rod of 

 y.mc being immersed in it, metallic tin was bv degrees di- 

 ptjsited in a duidrilie form, which when collected weiglud 

 ;J2 grains. 



T 3 A hun- 



