on the alleged Convey sion of Carbon into Silicon. 301 



the purpose of determining the quantity of silicon, if any, which 

 it might contain, from the fact just noticed of vitrified matter 

 having got accidentally into the crucible. — (R. H. B.) 



Twenty grains of precipitated copper were mixed with five 

 grains of paracyanogen, and placed in a covered and luted 

 porcelain crucible; this was placed in another crucible, also 

 covered and carefully luted, and the apparatus exposed to a 

 white heat for one hour and a half; when opened, the contents 

 consisted of numerous metallic globules, mixed with a black 

 powder ; these globules were malleable, and wholly dissolved 

 in nitric acid, whilst the black powder was consumed when 

 ignited in contact with atmospheric air. — (J. D. S.) 



Another experiment was made by rolling up some very thin 

 sheet-copper, so as to form a tube of considerable thickness, 

 into which five grains of paracyanogen were tightly rammed, 

 and each extremity of the tube secured by hammering; this was 

 placed in an earthen crucible, covered and tightly luted, along 

 with a platinum tube made of foil filled with paracyanogen, in 

 the same way as the copper one above described, and exposed 

 to a bright yellow heat for one hour and a half; when the cru- 

 cible was withdrawn and opened, the contents were found to be 

 fused into a button, which was only slightly malleable, break- 

 ing readily ; having removed the exterior of this button, which 

 adhered to the crucible, it was treated with nitric acid, which 

 left a residue having the appearance of gray metallic particles 

 mixed with black carbonaceous matter ; by ignition with ac- 

 cess of air the black powder burnt away, leaving a gray residue 

 entirely soluble in nitro-muriatic acid. — (J. D. S.) 



Having hitherto so completely foiled in our endeavours to 

 obtain results similar to those detailed by Dr. Brown in the 

 paper under consideration, we resolved to conclude our expe- 

 rimental examination of it, by endeavouring to procure silicic 

 acid, either with or without the admixture of carbonate of 

 potash, from ferrocyanide of potassium. These experiments 

 are not so satisfactory as the preceding ones, owing to the ener- 

 getic action of the mixed ferrocyanide and carbonate upon 

 wrought iron at the high temperatures, but are nevertheless 

 useful as serving to confirm the results we had previously ar- 

 rived at. 



An experiment was made upon ferrocyanide of potassium, 

 by drying it carefully, and pressing 700 grains of it into a co- 

 vered porcelain crucible, which was then carefully luted, and 

 when dry plunged into a paste of plaster of Paris contained in 

 a Hessian crucible ; this was well dried on a sand-bath, then 

 covered, luted, and exposed to a white heat for five hours ; 

 when withdrawn from the fire and opened whilst still warm, 



