78 Intelligence and Miscellaneous Articles. 



the hydrochloric and hydrosuljjhuric acid, gave rise to new acids 

 containing chlorine or sulphur ; oxalic and sulphuric acids decom- 

 posed it with the disengagement of prussic acid. No compounds of 

 fulminic acid and the alkalis, potash and soda, or barytes, &c., have 

 been obtained. In all the experiments performed with the inten- 

 tion of preparing these compounds, double combinations have always 

 been obtained, such as that of barytes with oxide of silver or of 

 copper, and these soon decomposed when attempts were made to 

 separate the oxide of silver or of copper. 



Sometime since, however, Mr. E. Davy described a method for 

 the preparation of fulminic acid ; according to his process it may be 

 obtained in combination with water, though only for a short time. 

 He prepares a pure solution of fulminic acid, by adding hydrate of 

 barytes to fulminate of zinc. This addition is to separate the oxide 

 of zinc, and to yield pure fulminate of barytes, which is readily de- 

 composed by the addition of dilute sulphuric acid. By the invita- 

 tion of M. Liebig, M. Fehlen undertook to repeat the experiments of 

 Mr. Davy. For this purpose, fulminate of protoxide of mercury was 

 digested for some time with an excess of metallic zinc ; by this a 

 solution of pure fulminate of zinc was obtained, free from any trace 

 of mercury. This solution treated with hydrochloric acid yielded a 

 very strong smell of hydrocyanic acid, and at the same time that of 

 cyanic acid was also perceptible. The salts of silver precipitated 

 this solution : the white precipitate obtained in abundance was com- 

 pletely dissolved in boiling water ; when dried it detonated strongly. 

 If the solution of fulminate of zinc be cautiously evaporated by a 

 water bath, a yellow powder is obtained, but a small portion of 

 ■which is soluble in water; the aqueous solution gives a light white 

 precipitate with the salts of silver, which does not detonate. The 

 portion which is insoluble in water dissolves with effervescence in 

 acids, and hydrocyanic acid is evolved ; if the yellow powder be 

 heated alone, it becomes white, oxide of zinc is obtained, and am- 

 monia evolved. The substance, which gives a lemon yellow with 

 the oxide of zinc, was not more minutely examined. 



Solution of barytes was added to some recently prepared fulmi- 

 nate of zinc, until the solution was strongly alkaline : a large quan- 

 tity of oxide of zinc was separated ; the excess of barytes was preci- 

 pitated bj' carbonic acid. The solution separated by filtration from 

 the carbonate of barytes, acted with the salts of silver and with acid 

 like fulminate of zinc ; thus it yielded with the salts of silver fulmi- 

 nate of silver, &c. If sulphuric acid be added to the solution of the 

 fulminate, all the barytes is precipitated. The filtered liquor, which, 

 according to Mr. Davy, ought to be pure fulminic acid, when ren- 

 dered alkaline by ammonia, gives nevertheless an abundant precipi- 

 tate of sulphuret of zinc Avhen treated with hydrosulphate of ammo- 

 nia ; the presence of oxide of zinc was also proved to exist in the 

 liquor by carbonate of soda ; the precipitate obtained by it when 

 heated by the blow-pipe exhibited all the properties of oxide of zinc. 

 Barytes, therefore, precipitates only a portion of the oxide from ful- 

 minate of zinc : there exists therefore, in solution a double salt, com- 

 posed of fulminic acid, oxide of zinc, and barytes ; the sulphuric aci^ 



