of light and of copper on fermentation. 365 
(1) The optical activity for 100 °/ 0 solutions at 15° C. 
dark = +7’86° 
white = + 6*94 
red = + 7‘32 
blue = + 6-54 
(2) The copper oxide reducing power in 20 c.c. of a 20 °/ 0 
solution gave : 
dark = 0-1 170 gm. Cu. 
white =0 , 0980 „ 
red =0 , 1015 „ 
blue = 0-0860 „ 
(3) The specific gravity gave : 
dark = 987 '40 
white = 987*39 
red = 987*11 
blue = 987-13 
(4) The nitrogen content ; 10 c.c. of each of the fermentations 
N 
were used in the Kjeldahl method and 25 c.c. — acid used to 
10 
N 
The number of c.c. of acid 
neutralise the NH S distilled 
required to neutralise the NH 3 were: 
dark =7'95c.c. 
white =8-00 „ 
red =7 -85 „ 
blue =7-95 „ 
These numbers appear to prove that there is little or no effect 
upon the nitrogen assimilation or solution. 
(5) The acidity. The following numbers represent the number 
N . . 
of c.c. of — alkali used in the neutralisation. 
dark =13‘6c.c. 
white =13-8 ,, 
red =15-1 „ 
blue = 13-7 „ 
III. The following is the analysis of the unfermented wort. 
Optical activity for 100 °/ 0 solution = + 6-96°. 
The copper oxide reducing power for 20 c.c. of a 20 °/ 0 solution 
= 0-197 Cu. 
N 
The nitrogen content ; 25 c.c. of ^ H. 2 S0 4 were used and 
