Baron and Silicon with Nitrogen. 271 



suggest themselves to the mind of the chemist, and as my time 

 is of necessity devoted to other objects and my means very 

 limited, I beg leave to lay the few facts which I have been 

 able to ascertain before the working chemists of the day through 

 the medium of the Philosophical Magazine. 



Silica and boracic acid undergo no change when heated 

 in ammoniacal gas by means of the oxyhydrogen flame nearly 

 to the point at which platina melts, but when heated to that 

 temperature with cyanide of potassium instead of ammonia, 

 apparent action ensues. Boracic acid and cyanide of potas- 

 sium, in the proportion of two atoms of the former to three 

 of the latter, were placed in a covered porcelain crucible, that 

 inclosed in a larger Hessian crucible, and the space between 

 being filled with small pieces of charcoal, the whole was heated 

 to whiteness in a wind furnace. The result was a white porous 

 substance, which was found not only at the bottom of the cru- 

 cible, but also lining the sides and the top, having been carried 

 there by spurious sublimation. The relative quantities given 

 above were used in order that the carbon of the cyanide might 

 be exactly in the right proportion for taking all the oxygen from 

 the boracic acid and forming carbonic oxide only, and when 

 by accident an excess of boracic acid or cyanide was employed 

 it appeared to remain as an impurity in the white solid; but 

 these points were not closely examined, because the white solid, 

 which was homogeneous and evidently a distinct and stable 

 compound, was a more interesting object of study. The fol- 

 lowing is the best process for preparing it : — Take seven parts 

 of finely powdered anhydrous boracic acid and twenty parts 

 of cyanide of potassium free from water, and as far as possible 

 from cyanide of potass and iron ; and having lined a Hessian 

 crucible with a paste of powdered charcoal and gum, and 

 heated it until all water has passed away, place the mixture 

 in the crucible, cover it by inverting and luting a smaller cru- 

 cible over it, and heat it to whiteness for an hour : it is ad- 

 visable to use a crucible as a cover, that there may be suffi- 

 cient room for spurious sublimation, and the vent-hole should 

 be bored in the bottom of this crucible and not in the luting 

 at the side; and further, to avoid the penetration of oxygen 

 to the materials, it is well to line the upper crucible in like 

 manner with the lower. The result found in both crucibles, 

 when washed and dried, will be the white solid in a state 

 of purity. It is a light porous solid which readily falls to 

 powder, and when compressed, presents that peculiar sur- 

 face which is observable in some of the precipitated cyanu- 

 rets, and in a slight degree in chloride of silver, and in 

 some iodides, &c. ; it is infusible, insoluble, even when 

 heated, in water, in solution of potass, hydrochloric acid, sul- 



