1824.] Analysis of the Fulminate of Silver. 413 



ments, but which, upon closer examination, he pronounces to 

 be cotemporaneous concretions ; for large crystals of felspar may 

 be seen shooting from the porphyritic granite into these apparent 

 fragments. These phenomena are extremely interesting in a 

 geological point of view, and well deserve the attention of the 

 scientific tourist. 



Article V. 



Analysis of the Fulminate of Silver. By MM. Liebig and 



Gay-Lussac* 



The memoir published by one of us upon fulminating silver 

 and mercury, prepared by means of nitric acid and alcohol, was 

 principally intended to show that these compounds are true salts 

 formed by peculiar acids which may be separated from them, 

 and combined with all other bases. Their analysis, and espe- 

 cially those of the acids, opposed too many difficulties to allow 

 of the flattering conclusion, that these were given with accuracy 

 on this first essay; and being both of us persuaded of the possi- 

 bility of effecting them with a greater degree of precision, we 

 united to make this analysis the subject of fresh researches. 



Fulminate of silver being very easily prepared, and its insolu- 

 bility allowing of its being had perfectly pure, we selected it in 

 preference to other fulminates to submit it to experiment. 



The process by which we prepared it differed but little from 

 those which have been given; nevertheless it occurred to us 

 that it might not be useless to state the manipulations of it. 



Put into a pint matrass 700 grs. of nitric acid, of specific gra- 

 vity l - 36, or 1*38, and 34 grs. of pure silver. When the silver 

 is dissolved, the solution is to be poured into 1000 grains of 

 alcohol of 85 to 87 centisimal degrees. The fluid when heated 

 to ebullition soon becomes turbid, and begins to deposit fulmi- 

 nate of silver : the matrass is then to be removed from the fire, 

 and in order to diminish the ebullition, which still continues, a 

 quantity of alcohol equal to that originally employed is to be 

 gradually added. When the ebullition has ceased, it is to be 

 suffered to cool, the fulminate is to be put upon a filter, and 

 washed till it ceases to yield any acid. The fulminate is then 

 snow-white and quite pure. The filter is then to be removed, 

 and spread upon a plate, and covered with paper ; it is to be 



E laced upon a vessel half filled with water, which is to be kept 

 oiling for two or three hours. The weight of fulminate obtained 

 is usually equal to that of the silver employed ; a third more 



• Annalcs dc Chimic ct tic Physique, tome jutv. p. 285. 



