Dr. Hare’s Reply to Prof. Vanuaxem. Ooi 
interesting phenomena observed by Professor Silliman, do 
not to me ap pear to be dependent for their importance on 
the nature of the projection which arises on carbon, when 
forming the negative pole of the deflagrator. That such an 
excrescence arises, and that a corrresponding 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 so- 
Jution 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 years 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 sixteen 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 af- 
fected 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 metallic polish, it was friabie, and the fragments were 
without brilllancy. Seen by the aid of a powerful micro- 
scope, 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 
mentioned was made, | 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 
* | 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 
together, when one is not enough. Persous not provided with proper 
‘pectacles, may use a piece of card, or paper, pierced with some fine holes. 
Through a hole made by a pin, the phenomena may be viewed satifacto- 
rily. 
