RussiUn Expedition to Juparn 115 



larger quantity, it \i because there are four-fifths of tin ab- 

 sorbed by the alkaUne flux. 



To deterniiue the quantity of lead contained in the tin 

 extracted from the amalgam of mirrors, I decomposed a 

 hundred parts of it by four hundred parts of nitric acid at 

 32^. A great deal of nitrous gas was disengaged, and there 

 remained at the bottom of the matrass a white magma. I 

 washed it with distilled water, and evaporated the ley^ which . 

 produced a twenty-fifth of nitrous ammoniacal salt mixed 

 with nitrate of lead, which predominates, and forms nearly 

 two-thirds of the saline residuum ; a proportion which 

 would indicate that the tin employed for silvering mirrors 

 contains three pounds of lead per quintal. 



I now return to the mercury extracted by distillation from 

 this amalgam. It volatilizes a portion of tin, which remains 

 there so intimately combined that it cannot be separated by 

 a second distillation of the mercury. I was able to disengage. 

 from it the tin by shaking the mercury with nitric acid, 

 which attacks and oxidates the tin. I washed the mercury 

 and strained it through a piece of linen. In this state it 

 may be employed for gilding, but when it contains the 

 smallest quantity of tin it stains the articles. 



What I have related in this memoir shows that red oxide 

 of iron, known under the name of colcothar, is not proper 

 for polishing glass when it contains vitriol ; that the tin 

 employed for silvering mirrors contains lead and iron ; that 

 when this tin is separated from the mercury by distillation 

 this metal crystallizes with the greatest facility and without 

 any precaution ; and, in the last place, it is shown that a 

 portion of tin is volatilized bv the mercury during the di- 

 stillation of the amalgam, and that it cannot be separated 

 but by the nitric acid. 



XVIir. Extract of tuo Letters froni Captain Yon Kru- 

 si-:xsTEiiN, Commander of the Russian Expedition to 

 Japan, dated the Harbour of St, Peter and St. Paul, 

 July ig, and August 20, 1804. 



[Concluded from p. 13.] 



X HE Frenchman is now at Kamtchatka. I shall mention 

 hereafter by what accident he remained on board the ship. 

 This man is a singular phainomenon : he had forgotten his 

 own name, those of his father and mother, and that of the 

 place from which he came. He sung to us some patriotic 

 II !2 songs. 



