20 THE ROYAL SOCIETY OF CANADA 
clusive. We believe that the only question left even partly open is 
4, and that only to the extent that the most carefully conducted quan- 
titative determination is always subject to revision. 
Experimental 
The polarimeter used in all the experiments here recorded was a 
Schmidt & Haensch Triple Field instrument, graduated to read in 
Ventzke sugar divisions (to 0-1 division) ef the dimensions fixed for 
‘7’ light. Where our figures are carried to a second decimal place 
this indicates that they are the mean of two or more readings differing 
by not more than 0-1 division. The length of the polariscope tube 
used in all these experiments was 2 d.m. The source of light 
was a tungsten incandescent lamp, suitably shaded.. All readings are 
given in Ventzke sugar scale divisions of ‘‘j’’ light dimension. Ob- 
servations were made at 24°, which may be considered an average 
laboratory temperature. 
Influence of Dilution on the Rotatory Power of Aqueous Nicotine 
Solutions. Our experiments on this point were made in two series. 
Series A. Pure nicotine was dissolved in water, giving Solution 
I, the strength of which was approximately 2-5%. Solution II was 
obtained from this by diluting 250 cb.c. to 500 cb.c., while Solution 
III was in turn obtained by diluting 50 cb.c. of II to 100 cb.c. 
Series B. Solution I was made by dissolving pure nicotine 
in water, its strength being approximately 1-5%. The dilution of 
50 cb.c. of this solution to 100 cb.c. gave Solution II, while 25 cb.c. of 
Solution I diluted to 100 cb.c. gave Solution ITI. 
The rotatory power of these six solutions was then determined. 
The results are shown in the following table. 




Series A. Series B. 
Solution Observed Rotation in Solution Observed Rotation in 
number Sugar Scale Divisions number Sugar Scale Divisions 
I — 11-8 I — 6-7 
II — 5-9 II — 3-35 
III — 2-95 III — 1-7 



These results show clearly the directness of the relation between 
the dilution and rotatory power of the solution examined. Their 
bearing will be discussed later. 
