542 Intelligence and Miscellaneous Articles. 
and when washed with water and hydrochloric acid, it appears in 
the form of an extremely fine bright powder. If allowed to swim 
on the top of the almost red-hot fused soda, the graphite is oxidized 
gradually, and after the lapse of about three or four hours it alto- 
gether disappears. Heated in a platinum crucible by itself it is in- 
combustible ; but it generally contains small particles of charcoal 
mixed with it, and these undergo oxidation, 
The temperature at which this evolution of graphite takes place is 
a very low one, compared with that at which graphite is liberated 
from cast iron; for a thin iron wire can scarcely be brought to a 
visible red heat by dipping it into the fused alkali. 
From this peculiar decomposition it would appear that we have 
good reason to assume that the carbon contained in cyanogen is pre- 
sent in the graphite modification ; for if this be not the case, how is 
it that the easily combustible charcoal can withstand the oxidizing 
action of the saltpetre, whilst none of the iron of the ferrocyanide of 
sodium is reduced to the metallic state. 
It has, besides, been lately shown by M. Caron, that the forma- 
tion of steel, 7. e, the combination of iron with carbon in the graphite 
modification, can only take place in presence of cyanogen compounds, 
and that no carbon whatever is taken up by the iron when this metal 
is heated with other carboniferous gases. ‘The mode of production 
of graphite noticed in this communication appears to be an interme- 
diate reaction between that from the carbide of iron and from the 
nitride of carbon. 
As in the process of cementation it is seen that the carbon of the 
cyanogen is taken up by the iron without being set free, so this re- 
action proves that cyanogen can be split up into its constituent parts 
without either of them combining with a third body. 
Despretz asserts that the carbonization of iron is always preceded 
by a combination of this metal with nitrogen, a process which makes 
it porous and more fit for uniting with carbon, The correctness of this 
supposition has, however, become rather doubtful, by Caron’s recentl 
published experiments (Comptes Rendus, Nos. 15 and 24, 1860). 
To conclude, I beg to say some words about the formation of 
native graphite; I do not think that this body has been formed from 
coal or diamond, but I rather believe it has been separated out of 
carbon compounds as graphite, by processes perhaps anaiogous to 
those above described.— Proc. Manchester Phil. Soc., April 16, 1861. 
ON ELECTRICAL PARTIAL DISCHARGES. BY P. RIESS. 
To the Editors of the Philosophical Magazine and Journal. 
GENTLEMEN, 
Professor Rijke has met with a difficulty in the explanation of 
Wheatstone’s experiments on the discharge of a Leyden jar, and has 
himself instituted experiments*, from which it seems that more elec- 
tricity remains on a conductor when it is discharged through a wet 
string than when it is discharged through a metallic wire. 
I do not think that this difficulty exists, nor that these experiments 
have any claim to novelty. ‘'wenty years ago I showed that when 
* Phil. Mag. for May, p, 365. 
