38 
BRITISH ASSOCIATION.— 1835. 
practical nature, as whether its root contained nicotin, and in what 
quantity, and to ascertain the comparative value of Irish and Vir¬ 
ginian tobacco. 
The author’s experiments were made on average samples of Vir¬ 
ginian and Irish tobacco; for the former he was indebted to the 
kindness of Mr. Simon Foot, and for the latter to Messrs. Wild, 
Cuthbert, Callwell, and Brodigan. From a number of experiments 
the author was led to conclude that the dried roots of Irish tobacco 
contain from four to five parts of nicotin in one hundred parts; and 
that one pound of good Virginian tobacco is equivalent in value to 
about 2-j- pounds of good Irish tobacco. 
After the author had finished his experiments it was gratifying 
to him to be informed that some manufacturers estimate one pound 
of Virginian tobacco as equivalent in value to about two pounds 
of Irish. Hence there seems to be a pretty near coincidence be¬ 
tween their results and those derived from a chemical examination. 
On Nicotin and some of its Combinations. By Edmund Davyj 
F.R.S ., M.R.I.A., <^c., Professor of Chemistry to the Royal 
Dublin Society. 
When the author commenced his experiments in 1829 on Irish 
and Virginian tobacco, nearly all our knowledge of the peculiar 
principle in tobacco, called Nicotin by the late M. Vauquelin, was 
confined to his paper on tobacco*. By a series of processes in which 
the expressed juice of tobacco was reduced to one fourth of its 
bulk by evaporation, then digested in alcohol, distilled, again con¬ 
centrated, dissolved in alcohol, then evaporated to dryness, dissolved 
in water, saturated with potash, and distilled to dryness, Vauquelin 
seems to have obtained a fluid nearly approximating to the nicotin 
recently procured. 
In obtaining nicotin, the author avoided the circuitous processes 
of Vauquelin, and adopted only the simple method of exposing to¬ 
bacco to the action of a solution of potash and subsequent distilla¬ 
tion. The alkali employed was in some cases weak and in others 
strong. In some instances it was macerated on the tobacco for one 
or two days; in others, it was added to the tobacco in the retort 
and distilled at once. Other fixed alkaline substances in solution, 
as soda, barytes, strontites, lime, may be substituted for potash. 
Distillation was occasionally carried on below, but in general at the 
boiling-point. Under such varied circumstances, the fluid procured, 
on being rectified by a second distillation, is an aqueous solution of 
nicotin, having the following properties. It is colourless and trans¬ 
parent. Its odour closely resembles that of tobacco, but is far more 
pungent. Its taste is peculiar, and leaves a sharp biting impression 
on the tongue for some time. It changes turmeric paper to brown; 
* Annates de Chimie, tome lxxi. 
