40 
BRITISH ASSOCIATION.— 1835 . 
December 1829, that MM. Posselt and Reimann had lately obtained 
a vegeto-alkali from tobacco, examined its properties, and combined 
it with a number of acids. But though those chemists are justly 
entitled to the merit of having first made known to the public an 
interesting series of facts respecting nicotin, the author’s experiments 
may serve to corroborate their general results, and also throw addi¬ 
tional light on the subject. 
On a Fluid obtained in the manufacture of Pyroxylic Spirit. 
By M. Scanlan. 
The author has been for some time past engaged in the making 
of pyroxylic spirit, a fluid now extensively used in England (under 
the name of ‘ Naphtha’) as a substitute for alcohol, principally by 
hat-manufacturers, for the purpose of dissolving shell lac and mastic 
to stiffen their hats and render them water-proof. 
In the process which Mr. Scanlan pursues, he obtains a fluid of 
a higher specific gravity, but having a lower boiling-point than py¬ 
roxylic spirit, and differing from it in other respects. 
Rough pyroligneous acid is submitted to distillation in a copper 
still, by the maker, in order to separate some of the tar it holds in 
solution ; he sets apart the first 15 per cent, that distils over, and 
this he sells as wood-spirit. This liquor, as it comes from the py¬ 
roligneous acid-maker, contains much free acetic acid and tarry 
matter. 
The author proceeds to saturate the acetic acid by means of 
slacked lime, which causes the separation of some pitch. 
He next submits the saturated liquor to distillation as long as 
the distilled product is of less specific gravity than water. 
This last product is rectified in a still somewhat on the plan of 
those for a long time in use on the Continent, and now coming into 
general use in this country, for the purpose of rectifying spirit. It 
consists of a boiler, containing the liquor submitted to distillation, 
and of a rectifier, which is a copper vessel of peculiar construction, 
placed in a bath of water, which must be kept at such a temperature 
as will condense water, but still retain the more volatile products in 
the state of vapour till they pass into the last part of the apparatus, 
where they are condensed and finally cooled. 
In this process of rectifying, the author was a good deal sur¬ 
prised to find the product first condensed had a higher specific gra¬ 
vity than that which succeeded to it in the distillation. The first 
being about *900, and the second so low as *830 ; to this, if the di¬ 
stillation be pushed far enough, succeed water and an oil which 
becomes black by keeping. The fluid having specific gravity *900, 
is a good deal coloured; treated with animal charcoal its colour is 
removed; rectified from a w r ater-bath after treatment with animal 
charcoal, its specific gravity is *911, and its boiling-point about 
132 °. 
