152 REPORT OF THE CHEMIST OF THE 
of this work are given in the following table, only the amounts 
of total acid being given: 
TABLE XI.—INFLUENCE OF TEMPERATURE UPON FORMATION OF 
ACID. 
Percentage of total acid in cider kept at temperature of 
AGE. 
bya? Ws 60° F. 65°UH. 70° F. 85° F. 
| 
Months. Per ct. Per ct. Per ct. Per ct. Per ct. 
es Pres ay ste aa forave PAN bg 1.46 2.29 0.78 0.28 
iREa? Cae BApaa Coe Poe 3.63 4.32 7.03 4.99 0.35 
LONE rai Re Teen abe coe ae 4.45 4.81 7.67 7.05 3.45 
1 SS CR OT 3.03 5.41 6.88 Le7Ge 4.23 
ere erence ale ere le 2.73 ez 7.02 sts 4.39 
21. 1.43 4.87 6.94 7.79 6.53 
60. 0.00 0.00 | 8.86 8.46 | 6.77 
A study of the data in Table XI suggests the following state- 
ments: 
(1) The highest amounts of acetic acid were obtained when 
the fermentation was carried on at 65° and 70° F. and this was 
true at any given time after the third month. 
(2) At 85° F. the fermentation was slowest in starting but 
gave a continuously increasing amount of acid for 21 months; 
at this time the amount of acid formed was higher than at 55° 
or 60° F. 
(3) While acetic fermentation started quite promptly at boa ae 
it reached its maximum in nine months and this was considerably 
lower than the maximum reached at the other temperatures. 
After the ninth month, the acid decreased continuously, evidently 
undergoing a destructive fermentation, and finally disappeared 
altogether. At 60° F. there was something of this loss of acid 
put not so marked as at 55° F. during 21 months but later the 
acid all disappeared. This loss did not occur at the other tem- 
peratures during the 21 months in which the work was continued. 
(4) So far as the results furnish evidence we can look for the 
most satisfactory results of acetic fermentation, all things con- 
sidered, at temperatures between 65° and 75° F. 
The influence of adding vinegar to cider wpon the acetic fermen- 
tation.—When at the end of eight months the alcoholic fermen- 
tation was complete, we added to each of several 10-gallon casks 
