194 Miscellanies. 



of acting as an assistant, I have taken up my pen to give you a brief 

 statement of their results. 



A considerable quantity of paracyanogen was obtained by exposing 

 the bicyanide of mercury to a low red heat, according to the direction 

 given by Brown, in an iron tube closed air tight by a plug of the same 

 metal, traversed by a perforation filled with stucco. During the ope- 

 ration the vapor of mercury with a part of the cyanogen, escaped 

 through the orifice by passing through the pores of the stucco, while 

 the i-emainder of that gas was converted into paracyanogen and re- 

 mained in the tube in the shape of a black porous mass. So far, as 

 might easily have been anticipated, the results obtained agreed with 

 those indicated by Brown, as his coincided with those of previous ex- 

 perimenters. On exposing however the paracyanogen resulting from 

 this process to heat in glass tubes, instead of the evolution of niti'ogen 

 and the conversion of the carbon into silicon, carburets of nitrogen, 

 in which more or less cyanogen was present, were given off, and the 

 residue appeared to consist of carbon and not of silicon. This result 

 entirely agreed with the habitudes of paracyanogen, as described in 

 works on chemistry, and was equally inconsistent with the statements 

 of Mr. Brown. 



With the view of making an experiment on a larger scale, which 

 should prove decisive of the facts in question, the iron tube above de- 

 scribed was again charged with five or six ounces of the bicj^anide of 

 mercury, and kept for several days at a heat just below redness. The 

 vapor of mercury was given off through the stucco during the whole 

 period, but as far as could be determined by the absence of odor and 

 the application of a lighted taper of flame, unaccompanied by any 

 cyanogen. This treatment should, according to the experiments of 

 Mr. Brown, when continued during such a length of time, have been 

 alone sufficient- to determine the formation of silicon. The tube was 

 then heated to redness in a wind furnace for four hours, and subse- 

 quently kept at a white heat for as many more. On opening it, the 

 whole of the materials were found to have been volatilized, while the 

 iron of the tube remained unchanged, except that in one or two places 

 a few scales had been formed. These, when detached and dissolved 

 in muriatic acid, left a small quantity of the carbonaceous residue 

 which remains after the solution of ii'on in that solvent. 



As the heat applied to the bicyanide before it was placed in the fur- 

 r^ce, must necessarily have converted the greater portion of the cya- 

 nogen which it contained into paracyanogen, and according to the ex- 

 periments of Mr. Brown, should have worked the farther change of a 

 considerable portion of the carbon into silicon, while the succeeding 

 part of the process, if his views were correct, would have completed 



