188 PROCEEDINGS OF THE AMERICAN ACADEMY. 



salt contains 18 molecules of crystal water, a portion of which goes 

 off quickly in the air or over sulphuric acid in a vacuum, and the 

 substance changes its color first to white and then slowly to red. A 

 concentrated aqueous solution of the salt is precipitated by alcohol, 

 first in yellow needles, and on addition of more alcohol these are 

 suddenly transformed into a colorless white powder with loss of a 

 portion of the crystal water. 



Whereas, the double salt. AgON : C, KON : C, is far more stable 

 than the corresponding prussic acid double salt, AgN : C, KN : C, in 

 this case the ferrofulminate of soda is far less stable than the analo- 

 gous sodic-ferrocyanide. It does not give an acid, ferrofulminic acid 

 corresponding to ferrocyanic acid, and, even on losing its crystal water, 

 the salt Na6Fe(0N : C)6 + 18 HgO dissociates completely into sodic 

 fulminate, NaON : C, and into ferrous fulminate, Fe(ON : C)2. 



On treating the salt in the cold with dilute hydrochloric acid, it is 

 converted into formylchloridoxime. Also on boiling it in aqueous 

 solution with sodic hydrate or with ammonium sulphide, it is slowly 

 decomposed, with separation of iron hydrate or iron sulphide. 



An aqueous solution of the salt gives with lead acetate, silver ni- 

 trate, or mercuric chloride, white very explosive precipitates, which 

 appear to consist exclusively of the corresponding fulminic acid salts. 



As mentioned above, the yellow salt easily loses a portion of its 

 crystal water and becomes colored white ; on addition of water, it 

 is again transformed completely into the original salt. After long 

 standing over sulphuric acid in a vacuum, the white salt becomes 

 tinged red, and finally is converted into a red powder, which no longer 

 consists of ferrofulminate of soda, but of a mixture of sodic fulminate 

 and ferrous fulminate ; it then dissolves only partly in water, leaving 

 behind a red powder, and the solution does not contain a trace of sodic 

 ferrofulminate. On adding sodic hydrate, however, union of the com- 

 ponents again takes place, and the solution contains sodic ferrofulmi- 

 nate, which can be obtained on allowing the solution to evaporate. 



The red dissociated salt just mentioned possesses very explosive 

 properties. It is just as dangerous as sodic fulminate,* and on this 

 account it was never possible to carry out a complete analysis of the 

 salt ; even when mixed very carefully with oxide of copper, on heat- 

 ing invariably a violent explosion took place. t The quantitative 



* Journ. f. prakt. Cliem., [2.], XXXII. 231. 



t The explosion is so sudden that not a gas bubble appears in the potash bulb 

 (5 times noticed), and the combustion tube is shattered completely only where 

 the substance was present. 



