[TINGLE-FERGUSON] AQUEOUS SOLUTIONS OF NICOTINE. 31 
The objections to the method of Kissling are well known. Its 
good results are recognized as being due to balancing errors. As 
applied to tobacco extracts containing pyridine or its homologues, it is 
acknowledged that the methods of Téth and Kissling are alike useless. 
The method proposed by Emery for the determination of nicotine 
in tobacco only differs from that of Kissling in that the final distillate 
instead of being titrated is diluted to exactly 500 cb.c. and then 
examined polarimetrically. Our objection to this method is two-fold. 
Firstly, it perpetuates the danger inherent in the Kissling method, of 
losing nicotine, while it removes the compensating error of the possible 
retention of ammonia; secondly, it gives readings on the polarimeter 
so low that the probable error of observation becomes relatively high. 
As an example of this last objection we may take the results given 
in our own Experiment 1 quoted above. Had the distillate in this 
case been diluted to 500 cb.c. and examined in a 4 d.m. tube, the 
rotation would have been only — 0-8 sugar divisions (— 0-3124° 
circular). Further, in our experience the polarimeters most fre- 
quently in use will not accommodate so long a tube. If a 2 d.m, 
tube were used, the rotation would be — 0-4 sugar divisions only. 
We consider therefore that Emery’s method for tobacco would entirely 
fail in practice. Our own, especially as modified in Experiment 2, 
is much quicker than his. 
