236 On the Combination of Antimony ivith Tin. 



but by a great quantity of potash ; it is sufficient to boll the 

 liquor some time in order to burn the hydro-sulphuret ; and, 

 besides, the sulphurated hydrogen is separated by the acid 

 of the alum. In short, the operation would be very much 

 abridged, if, instead of washing the prussiate of iron in a 

 great quantity of water, it was only mixed with a small quan- 

 tity of oxygenated muriate of lime. 



Such are the observations which I considered it my duty 

 to collect in tbe present memoir j the whole facts do not be- 

 long to my subject. In order to support those which do, 

 I have connected with them some observations which were 

 the result of the labours of different chemists. Sometimes 

 I have even repeated facts known long ago, in order to pre- 

 sent at one view the properties of a body, 6r the track we 

 ought to follow in an operation. Yet still, I believe, I have 

 examined, with some advantage to the arts and sciences, the 

 oxidation of iron and the combinations of its oxides with 

 acids. The existence of the white oxide of iron will make 

 us acquainted with various phsenomena the causes of which 

 •were hitherto unknown ; it explains, in particular, that va- 

 riety of colours which all the ferruginous salts present to us. 

 It spreads some light on one of the finest and most important 

 dyes known, viz. that of black. It does not throw less light 

 on the manufacture of Prussian blue, upon the improvement 

 of which much yet remains to be done. In short, it deeply 

 concerns the art of obtaining sulphate of iron, the perfec- 

 tion of which becomes dally more and more desirable. 



XLII. On the Comhination of Antiynony with Tin. By 

 M. Thenard*. 



X WAS led, about a year ago, to make the observations I am 

 now about to communicate, upon examining an alloy at- 

 tempted to be introduced into commerce, and to which such 

 miraculous properties were improperly attributed, that, ac- 

 cording to some accounts, it might have been substituted 

 in place of silver. 



* From Aiinuks dc Chimic, tome Iv, 



It 



