270 
WOOD SPIRIT AND ITS DETECTION. 
study at the hands of the chemist within the last ten or twelve years. Numerous highly 
complex acids, neutral substances, and bases, have rewarded the time and labour expended 
on their investigation, by the acquirement of both fame and riches for the discoverer— 
fame owing to the great scientific value of the results, and riches in consequence of their 
practical application. The number and complexity of the compounds formed during the 
destructive process cease to surprise us, when we consider the ever-changing circum¬ 
stances under which they are produced. To take an instance intimately connected with the 
subject of the present paper; let us suppose a block of wood placed in a close cylinder, 
and submitted to a gradually increasing temperature. The essential constituents of this 
block are carbon, hydrogen, oxygen, and nitrogen, all in different states of combination 
both on the surface and in the interior of the mass. On the first application of heat, the 
strictly organic structures are broken up superficially, their elements entering into new 
combinations, in which state they are volatilized. On the still further increase of tem¬ 
perature, the next succeeding layers undergo a similar process; but now, owing to the 
alteration of temperature, and probably in consequence of the different proportions and 
arrangements of the proximate constituents, another set of affinities come into play: the 
result of this is, as might be anticipated, the production of many new compounds, mate¬ 
rially different from those preceding them. Thus the process continues, the products 
altering in character as the temperature fluctuates. Such being the case, it ceases to be 
a matter of wonder that the compounds formed should be both numerous and variable, 
or that the examination of these should open an almost inexhaustible field of research to 
the scientific explorer. 
My object in laying the present communication before the Society is to bring forward 
a new and reliable test for the detection of pyroxylic spirit, and likewise to give a brief 
preliminary notice of some experimental results which I have obtained in the course of 
an investigation undertaken with a view to the complete separation of the more volatile 
constituents of wood naphtha. 
As pyroxylic spirit in its purest commercial form has been the subject of most of my 
experiments, it may be interesting to describe briefly the process by which it is manu¬ 
factured on the large scale. 
When wood is distilled in close vessels, and at high temperatures, it yields a variety of 
products, which may be classed under three heads—solid, liquid, and gaseous. The solid 
and gaseous products, not being connected with our present subject, may be dismissed 
without further comment, our attention being solely confined to the liquid portions. The 
tarry mixture which is the result of the first operation is rectified, and the more volatile 
portions redistilled from lime or chalk, bv which means the acetic acid, which is present 
in large quantity in the crude liquor, is got rid of. The distillate then constitutes the 
rough wood-naphtha of commerce. When required for medicinal use, this is further 
purified as follows:—The crude material is largely diluted with water, by which means 
the oily hydrocarbons always present are precipitated, the last trace of these being after¬ 
wards removed by the action of oxidizing agents. The very weak methylic spirit thus 
produced is then frequently rectified per se, and finally over quick-lime until the specific 
gravity is reduced to about 800. It then constitutes medicinal naphtha. 
The spirituous liquid thus produced is far from pure, since it consists of a mixture of 
acetate methyl, of acetone, methylic alcohol, and other bodies, which have been as yet but 
very imperfectly examined. Were we to attempt to separate these impurities by frac¬ 
tional distillation alone, failure could only attend our efforts, as a comparison of the boil¬ 
ing points of the three bodies already mentioned will show. 
Acetate of methyl boils at 133° F. 
Acetone „ „ 133° F. 
Methylic alcohol „ 149° F. 
The separation of methylic alcohol can be easily effected by means of chloride of cal¬ 
cium, but other methods must be adopted for the purpose of investigating the remaining 
constituents of the spirit. 
When studying the deportment of various metallic salts with the purified naphtha, I 
observed the following reaction:—When a little solution of chloride of mercury was 
mixed with a few drops of the spirit, and then excess of potash added, the oxide of mer¬ 
cury first thrown down was speedily redissolved with the production of a clear solution. 
This result can be obtained in the cold, but is more rapidly brought about by the aid of 
a gentle heat. When acetic acid was added to the alkaline solution a yellowish-white 
