68 



Messrs. Glassford and Napier on the 



the crystals to assume a brownish colour, rendering them ex- 

 ceedingly friable ; this condition was therefore cautiously 

 avoided. They were then submitted to the following ana^ 

 lysis : — 25 grains were mixed with an equal weight of car- 

 bonate of potash and fused ; the silver obtained in three differ- 

 ent experiments was as follows : — 



25 grs. of the rhombic prisms gave of silver 

 25 grs. of the iiexagonal plates 



The cyanogen contained in these salts was determined as 

 follows : 25 grains of the crystals were dissolved and saturated 

 with nitrate of silver ; the precipitate, washed, dried, and after- 

 wards fused with carbonate of potash, gave of silver: — 



I. II. III. 



From the rhombic prisms . . . 25-80 25-55 25-7 Mean 25-68 

 From the hexagonal crystals . . 26-55 26-63 26-65 Mean 26 61 



The mean of these results corresponds with 26*00 of cya- 

 nogen in the hexagonal crystals, and 25*08 in the rhombs. 



The amount of potassium was not determined by experi- 

 ment, but calculated from the above results ; but from the fact 

 that a solution of the crystals had not the slightest effect upon 

 test papers, proves the absence of free potash ; and the pre- 

 cipitate formed by the addition of nitrate of silver to a solution 

 of the salt not being effected by nitric acid, proved that all the 

 potassium in the salt existed as a cyanide. 



The results of these analyses in the 100 parts are — 



. -^ en* r Silver . 53*72 



^ o rt i Cyanogen 26*00 



^ «^S LPo^^^ssium 19*28 



99-00 



« r Silver . 51*48 

 "g -< Cyanogen 25*08 

 J [ Potassium 18*59 

 P^ 95*15 



Calculated f Silver . 54*02 



without -< Cyanogen 26-40 



water. [^Potassium 19*58 



100*00 



Calculated 



with 



water. 



Silver . 

 Cyanogen 

 Potassium 

 Water . 



51-69 



25*27 



18*70 



4*34 



10000 



The water in these crystals was not ascertained by experi- 

 ment, as it seems to be retained up to the point of decom- 

 position, when cyanogen is also evolved ; but these results 

 correspond so closely with those calculated, that we have no 

 hesitation in giving the formula of the one as CyAg + CyK, 

 and the other as CyAg + CyK + HO. 



These crystals possess similar properties in every other re- 

 spect, and may afterwards be spoken of as one salt. They 

 are soluble in 8 parts of cold and in an equal weight of boiling 

 water ; are soluble in boiling alcohol, but are deposited again 



