Intelligence and Miscellaneous Articles. 393 



powder is confirmed by the existence of a corresponding compound, 

 which contains precisely twice as much stannic acid, and. which of 

 course is a bistannate of protoxide of gold. 



This was prepared and analysed by Berzelius, and was found to 

 consist of 



By expt 

 Six equivalents of peroxide of tin. . . . 5610 or 68'45 68-4G 

 One ... protoxide of gold. . 2586 31-55 31-54 



100- 100- 

 Ann. de Ch. et de Phys,, Juillet 1844. 



ON FULMINATING GOLD. BY M. FIGUIEB. 



The author remarks, that there exist two different theories with 

 respect to the constitution of fulminating gold ; Proust, BerthoUet 

 and some other chemists having considered it as a pure and simple 

 combination of ammonia and oxide of gold. M. Dumas, on the other 

 hand, in a work published in 1830, has stated the opinion that this 

 substance is a compound of one equivalent of azoturet of gold and 

 two equivalents of ammonia ; the azoturet of gold acting as an acid 

 towards the ammonia. 



M. Figuier is of opinion, that the theory of Proust and BerthoUet 

 is more in harmony with the facts of the case ; protoxide of gold 

 yields, like the auric acid, a detonating compound with ammonia; 

 and we must then admit, adopting the opinion of M. Dumas, a new 

 and corresponding azoturet of gold ; hitherto, however, no compound 

 whatever of azote and gold has been obtained. 



Added to this, the fulminating compounds of gold at present known 

 possess exactly the colour of the oxides which furnished them ; the 

 fulminating gold containing the protoxide, like the oxide itself, has 

 a violet-blue colour ; the fulminating gold, obtained by putting am- 

 monia in contact with teroxide of gold precipitated by nitric acid 

 from the aurate of potash, is, like the oxide itself, of an olive colour ; 

 lastly, that which is obtained by treating chloride of gold with* am- 

 monia is yellow, like the hydrated teroxide, separated cold by potash 

 from a dilute solution of the chloride of gold, or like the same oxide 

 precipitated by a weak acid from aurate of potash. The identity of 

 colour of the oxides of gold, and their corresponding fulminating 

 compounds, leads to the opinion that the oxide of gold enters in 

 these compounds without altering its nature, and that they are all 

 simple saline combinations of ammonia, in which the oxides act as 

 acids. 



M. Figuier insists principally on the fact, that the analyses of ful- 

 minating gold, containing auric acid, performed by M. Dumas, agree 

 perfectly with this mode of regarding these compounds. 



M, Dumas found the composition of fulminating gold prepared 

 with auric acid to be (Au'^Az) + AzH^ + H^O^ ; it is evident, how- 

 ever, that it maybe stated more simply thus, Au-0' + 2(AzH3), 

 that is to say, as representing a sub-aurate of ammonia. Moreover 

 fulminating gold, obtained with the chloride and ammonia, yielded 

 M. Dumas by analysis. 



