46 J. G. Draper — Effect of Temperature^ etc. 



The difference in temperature being 22° G. and the difference 

 in rotation 14-32°, we have 



r C. = -650° difference in rotation. 



That is, for every rise of one degree Centigrade the rotation 

 diminishes -650 or nearly two thirds of a degree in a solution 

 of sulphate of quinine in which there is one gram of alkaloid 



Effect of variation in the proportion of water. — A solution of 

 sulphate in water prepared as before and containing one gram 

 of alkaloid to 50 c. c. of solution when examined under a 

 variety of temperatures, gave as the average result 



(11) «=-1103°at8ir C. 



This solution diluted by an addition of 50 c. c. of dis- 

 tilled water by which v was raised from 50 to 100 gave under 

 a similar variety of temperatures the average 



(12) ^^=-5-18"at32°C. 



Adding 100 c. c. of water to the last solution and thereby 

 raising v to 200, gave under the same conditions 



(13) «--2-58°at31i°C. 

 Arranging these in a tabular form we have 



For (11) ;?-l..y=50-.«=- 11-03° 

 For (12) p=l'-v^lOO--a=:-b-ld,° 

 For (13) 7^= 1.. 17=200.. a'^- 2 -58° 



From these by the formula \a] j ^^2^x 100 we have 

 •- '-^ ixp 



For (11) Mi = =^/^^- Xl00=-250-70° at 31i° C. 

 For (12) My--^°^— Xl00=-235-45° at 32° C. 

 For (13) Mi =^^^^—X 100= -234-54° at 3U° C. 



Conclusions. 



(a.) In the case of the sulphate, as has also been shown by 

 Hesse and others, there is a greatly increased rotation power 

 imparted to the alkaloid by its union with the acid. In the 

 experiments presented the values are : for one gram of alkaloid 

 to 50 cubic centimeters of solution [«]y = — 154-30° at 25° C. 

 for the alkaloid : for one gram of alkaloid + sulphuric acid to 

 50 c. c. of solution in water [a] / = -258-18° at 21° C, which 

 applying the correction of -650° for each degree Centigrade 

 becomes [^1-]/ = -255-48° at 25° C. for the sulphate. 



(&.) The aqueous solution of sulphate shows the same changes 

 under the influence of temperature as the alcoholic solution of 



