56 DESCRIPTION OF AN APPARATUS FOR 



produced an effluvium, of which the smell was like that which had been ob- 

 served to be generated bj the silicuret of potassium. 



Similar results had been attained by the deflagration, in a like manner, of a 

 compound procured by passing cyanogen over quicklime, enclosed in a porce- 

 lain tube, heated to incandescence.* 



Phosphuret of calcium, when carefully prepared, and, subsequently, well 

 heated, was found to be an excellent conductor of the voltaic current evolved 

 from the apparatus above mentioned. Hence it was thought expedient to 

 expose it in the circuit of the deflagrator, both in an atmosphere of hydrogen 

 and in vacuo. The volatilization of phosphorus was so copious as to coat 

 nearly all the inner surface of the bell-glass with an opake film, in colour 

 resembling that of the oxide of phosphorus, generated by exposing this sub- 

 stance under hot water to a current of oxygen.f 



The phosphuret at first contracted in bulk, and finally was, for the most 

 part, volatilized. On the surface of the charcoal, adjoining the cavity in which 

 the phosphuret had been deflagrated, there was a light pulverulent matter, 

 which, thrown into water, effervesced, and, when rubbed upon a porcelain tile, 

 appeared to contain metallic spangles, which were oxydized by the consequent 

 exposure to atmospheric oxygen. 



In one of my experiments with the apparatus above described, portions of 

 the carbon forming the anode appeared to have undergone complete fusion, 

 and to have dropped in globules upon the cathode. When rubbed, these 

 globules had the colour and lustre of plumbago, and, by friction on paper, left 

 traces resembling those produced by that substance. They were susceptible 



* After the above mentioned experiments were made, I was led to believe that the compound, 

 obtained as above described by heating lime with bicyanide of mercury, contained fulminic acid, or 

 an analogous substance. The mass being dissolved in acetic acid, and the filtered solution sub- 

 jected to nitrate of mercury, a copious white precipitate resulted. This, being desiccated, proved 

 to be a fulminating powder. It exploded, between a hammer and anvil, with the sharp sound of 

 fulminating silver. 



t The compound usually designated as the phosphuret of calcium consists, according to Thom- 

 son, of one atom of phosphate of lime, as well as two atoms of pure phosphuret. Hence it is easy 

 to see that the oxygen which enters into the constitution of the oxide, deposited, as above men- 

 tioned, upon the interior surface of the bell-glass, is derived from the phosphate. 



