348 Fusion of Plumbago, 



or looks a little like pumice stone, only, it has the whiteness 

 of porcelain, graduating however into light grey, and oth- 

 er shades, as it recedes from the intense heat. In a 

 few instances I obtained upon the charcoal, when this 

 substance terminated both poles, distinct, limpid spheres, 

 and at other times they adhered to the frit like beads on a 

 string. Had we not been encouraged by the remarkable 

 facts already stated, it would appear very extravagant to ask 

 whether this white frit and these limpid spheres could arise 

 from carbon, volatilized in a white state even from charcoal 

 itself, and condensed in a form analagous to the diamond. 

 The rigorous and obvious experiments necessary to deter- 

 mine this question, it is not now practicable for me to make, 

 and I must in the mean time admit the possibility that alka- 

 line, and earthy impurities may have contributed to the result. 



In one instance contiguous to, but a little aside from the 

 charcoal points, I obtained isolated dark coloured globules 

 of melted charcoal, analogous to those of plumbago. 



The opinion which I formerly stated as to the passage of 

 a current from the copper to the zinc pole of the deflagrator, 

 is in my view, fully confirmed. Indeed, with the protec- 

 tion of green glasses, my eyes are sufficiently strong, to en- 

 able me to look steadily at the flame, during the whole of an 

 experiment, and I can distinctly observe matter in different 

 forms passing to the zinc pole, and collecting there, just as 

 we see dust, or other small bodies driven along by a com- 

 mon wind ; there is also an obvious tremor, produced in 

 the copper pole, when the instrument is in vigorous action, 

 and we can perceive an evident vibration produced, as if, by 

 the impulse of an elastic fluid striking against the opposite 

 pole. 



If, however, the opinion which you formerly suggested to 

 me, and which is countenanced by many facts, that the poles 

 of the deflagrator are reversed, the copper being positive 

 and the zinc negative be correct, the phenomena, as it re- 

 gards the course of the current, will accord, perfectly well, 

 with the received electrical hypothesis. 



The number of unmelted substances being now reduced to 

 two, namely, the anthracite, and the diamond, you will readily 

 suppose I did not neglect to make trial of them, as however, 

 the diamond is an absolute nonconductor and the anthracite 

 very little better, I cannot say I had any serious hopes of 



