Observations on Naphthaline. 13 
water, from which it separates, in cooling, in such a manner as 
to render the water milky, which was before transparent: a por- 
tion however still remains dissolved, for the water, when filtered, 
postesses in a slight degree the taste and odour of the substance, 
and after a few hours deposits it in minute crystals. 
Readily soluble in alcohol, and still more so in ether, at any 
temperature; the solubility, in either instance, greatly increased 
by increase of temperature. 
A solution of this substance in four times its weight of boiling 
alcohol becomes, in cooling, a solid crystalline mass. _ It is pre- 
cipitated from its solution in alcohol by water, without acquiring 
any additional weight. 
It is soluble in olive oil, and in oil of turpentine. 
It does not combine either with an aqueous solution of potash 
or ammonia ; nor is it sensibly affected by contact with ammo- 
niacal gas. 
Soluble in acetic and in oxalic acid, to each of which it com- 
municates a clear pink colour. A saturated hot acetic solution 
becomes a solid crystalline mass in cooling. 
It blackens sulphuric acid when boiled in it; the addition of 
water to the mixture having no other effect than to dilute the 
colour: neither does any precipitation take place upon saturat- 
ing the acid with ammonia. 
Sparingly soluble in hot muriatic acid, to which it communi- 
cates a purplish pink colour. 
When boiled in nitric acid, it both decomposes the acid, and 
is itself altered in its composition ; and, in cooling, is abundantly 
deposited in short acicular crystals aggregated in stelliform 
groups. These crystals pressed between folds of unsized paper, 
in order to separate the adhering acid, and then exposed to heat, 
are readily melted: in cooling, the migltel mass shows evident 
traces of acicular crystallization, and the crystals are of a yellow 
colour. This yellow substance is readily inflamed, burns with 
a bright fame, emits much smoke, and leaves a considerable 
residuum of carbon, 
Of all the characters of the white concrete substance described 
in this section, its ready disposition to crystallize is perhaps the 
most remarkable. 
If thrown into a red hot crucible, a dense white vapour arises 
from it; which being received into a bell glass placed over the 
crucible, is condensed round the lower part of the glass in the 
form of a white powder; but in the upper and cooler part of the 
lass distinctly crystalline plates are formed, of a beautiful silvery 
Rostre: 
A similar and equally beautiful crystallization may be obtained 
by boiling this substance in water, in a glass matrass joi: a 
ong 
