OF THE DESTETJCTIVE DISTILLATION OE BOOHEAD COAL. 
449 
with fuming nitric, or a mixture of nitric and sulphuric acids. If, into a flask of three 
or four ounces capacity, two drachms of fuming nitric acid be poured, and one drachm 
of the naphtha be added by small portions, with constant and brisk agitation, allowing 
the temperature to rise a little, but preventing it going too far by immersing the flask 
(still kept in motion) in very cold water, a point is reached when the temperature no 
longer rises, and it is seen that the mixture forms an emulsion of a red-brown colour, a 
layer of green but brilliant fluid floating on the surface; the whole is then poured 
into a very narrow conical glass and allowed to rest for a few minutes, by which time 
the fluid unacted on has risen to the surface. The lower portion having been removed 
and thrown into water by means of a pipette, furnished with a hollow caoutchouc ball to 
avoid suction with the lips, the indifferent hydrocarbon is transferred to a flask having 
a well-fitting stopper and containing a quantity of highly-concentrated nitric acid. 
When the above operation has been repeated until sufficient of the hydrocarbon has 
been accumulated in the flask, the latter is violently shaken to thoroughly mix the fluids, 
and on standing for some time separation into two layers takes place ; the lower, con- 
sisting of the acid, which has abstracted the chief part of the hydrocarbons removeable 
by it, is withdrawn by means of a pipette, and the operation is several times repeated. 
It is absolutely essential to correct results that this treatment be sufficiently performed. 
The acid being removed for the last time, the fluid is washed with a solution of caustic 
potash, which, by absorbing the nitrous fumes, removes the green colour. The indifferent 
hydrocarbon is then digested with sticks of potash to remove the water, and when appa- 
rently dry, is distilled several times over sodium. 
The fluids obtained as above are perfectly colourless, of a pleasant odour, resembling 
may-blossoms, very volatile, even at low temperatures, and having a density of about 
O' 72 5. If pieces of sodium be rapidly cut from a mass, so as to have only a very thin 
layer of soda, and are then thrown into the perfectly dry hydrocarbon, the coating of 
oxide is dissolved, the metal appearing of the lustre of silver, and may probably be thus 
kept for any length of time. 
My first experiments were made upon the fraction boiling between 115® and 121°, 
merely because that happened to be the largest, and it soon became evident that the 
hydrocarbon obtained by the process described, possessed the composition and the same 
degree of condensation in the state of vapour as butyle (valyle of Kolbe). But as it is 
evident that the formula C‘® H*® corresponds also to the hydruret of the radical of the 
caprylic alcohol, it was necessary to ascertain the correct boiling-points of the bodies 
obtained, because if coinciding with those of the radicals, it would be strong evidence 
of their identity with them. But the composition of the radicals differing but little, it 
is evident that analysis alone, however carefully made, cannot decide the question ; fortu- 
nately, however, the addition or subtraction of C^H^has a very considerable infiuence on 
their vapour-density, as will at once be seen by reference to the annexed Table, where 
the increase is compared with the rise of carbon and diminution of hydrogen as the 
boiling-point becomes higher. 
MDCCCLVII. 3 N 
