286 Dr. Hare on Fused Carbo7i, 



ties ai'e well known to be earth or alkali, with a very muiute 

 portion of iron, if an3% These facts, thus cited by him, are 

 therefore irreconcilable with his inference, that a piece of char- 

 coal of about an inch in length, and less than a quarter of an 

 inch in thickness, could, instantaneously, at its point, form a 

 projection of matter almost solely ferruginous. 



I will take this opportunity of observing, that the most in- 

 teresting phaenomena observed by Professor Silliman do not 

 to me appear to be dependent for their importance on the na- 

 ture of the projection which arises on carbon when forming 

 the negative pole of the deflagrator. That such an excres- 

 cence arises, and that a corresponding crater or pit takes 

 place in the charcoal on the opposite pole, are the facts which 

 principally interest me. 



I should have done more to prepare myself for the solution 

 of the doubts which have been excited respecting some of the 

 observations of Professor Silliman, had not my eyes been so 

 much affected by a powerful deflagrator, made about two j^ears 

 ago, as to be distressed by any subsequent employment of them 

 in the same way. 



From a cursory observation made last winter, I was led to 

 suppose the light of the deflagrator to be equal to that of six- 

 teen hundred candle flames, condensed within a space no larger 

 than that usually occupied by one. 



Since the above was written, in trying a deflagrator made 

 for Professor Nott, the operator had his eyes so much affected 

 as to be bloodshot next day*. 



By means of the same deflagrator a specimen of the fused or 

 volatilized charcoal was obtained. This did not prove to be 

 magnetic. Instead of being malleable, or susceptible of a me- 

 tallic polish, it was friable, and the fragments were without 

 brilliancy. Seen by the aid of a powerful microscope, before 

 it was broken, it was, both in colour and shape, exactly like 

 the depositions or concretions of carbon, which have been 

 formed in some instances during the gas-light process. 



P. S. It is remarkable that, since the observation last men- 

 tioned was made, I have found that Mr. Conybeare, in some 

 speculations on the concretions of carbon, noticed in gas-light 

 cylinders, infers, that they may have some analogy with the 

 products described by Professor Silliman as fused carbon. 



* I have considered it proper to dwell on the injury thus sustained by 

 the eyes, that others may by due caution, in the first instance, avoid the 

 evil. The deepest green spectacles should be used, putting two glasses to- 

 gethtr, when one is not enough. Persons not provided with proper spec- 

 tacles may use a piece of card, or paper, pierced with some fine holes. 

 Through a hole made by a pin the pha;nomcna may be viewed satisfac- 

 torily. 



XLVI. On 



