28 arty THE ROYAL SOCIETY OF CANADA 
fundamentally on the correctness of certain assumptions as to the 
polarimetric behaviour of aqueous nicotine solutions. 
These assumptions are: 
1. That the rotatory power of a solution of nicotine in water is 
not changed by the presence of alkalis or salts of alkalis in the solution. 
2. That acid solutions of nicotine sulphate may be evaporated 
without either loss of nicotine by vaporisation, or the occurrence of 
racemisation. 
3. That the rotatory power of an aqueous solution of nicotine 
containing three per cent of the base, or less, is proportioned to its 
concentration. - 
We believe experimental proof of the above has been satisfac- 
torily furnished by us in the preceding paper. (This Journal X. 10.) 
In the same place will also be found details of our determination 
of the rotatory power of nicotine in dilute aqueous solution. It is 
obvious that till this constant is known with reasonable accuracy no 
polarimetric determination of nicotine is reliable. 
Experimental 
We propose two alternative methods for the determination of 
nicotine, one of which is a slight modification of the other. These 
methods will be best understood by describing in detail their applica- 
tion to a particular case. For the sake of comparison details of de- 
terminations made on the same tobacco by the methods of Kissling 
and of Tôth are also given. 
The tobacco used in the following experiments was Canadian- 
grown leaf, dried at 110°, powdered, and passed through a 60-mesh 
sieve. 
Experiment 1, New Method. The sample, weighing 20 grammes, 
was placed in a 500 cb.c. flask with 40 grammes of barium hydroxide 
and 150 cb.c. of water. This mixture was distilled in a current 
of steam, gently at first, but afterwards as rapidly as was convenient. 
The heating was so arranged that the volume of mixture in the dis- 
tillation flask was ultimately reduced by about one-half. Distillation 
continued till a drop falling from the condenser gave no alkaline 
reaction with phenolphthalein. The whole distillate was then acidified 
by the addition of twenty cb.c. of sulphuric acid, transferred to an 
open dish, and evaporated on the water bath to about 50 cb.c. 
The concentrated solution thus obtained was again transferred to a 
100 cb.c. graduated flask, the evaporating dish being carefully washed 
and the washings added. The solution, thoroughly cooled, was made 
strongly alkaline by the addition of an excess of concentrated potassium 
