150 Report OF THE CHEMIST OF THB 
(3) Our work was not carried on in such a way as to show the 
amount of acetic acid formed by the alcohol present in ine hyuid. 
As we have previously stated, theoretical considerations call for | 
the production of 130 parts of acetic acid from 100 parts of 
alcohol, but the yield in actual practice has been found lower, 
probably below 120. 
(4) The fixed acid, which we have regarded as consisting 
chiefly of malic acid, decreased in amount as the cider became 
older. To this feature, we shall call special attention later. 
' (5) The specific gravity increased as the alcohol was converted 
into acetic acid, going from 0.9979 to about 1.02, when the alcohol 
had disappeared. A portion of the increase during the later 
months of the experiment was due to some evaporation of water. 
The influence of temperature upon the acetic fermentation of 
cider.—When at the end of about six months the alcoholic fer- 
mentation had been completed in experiments numbered 1 to 10, 
five of the casks were left in the cellar, and the other five were 
transferred to a room where the temperature was considerably 
higher. In the cellar the extremes of temperature during the 
year were 45° to 65° F., while in the other place the variation 
was between 50° to 90° F. The following table gives the aver- 
ages of the results secured under these two different conditions 
of temperature. It was designed to have the condition of the 
casks kept in the cellar approximate as nearly as possible the con- 
ditions commonly observed by farmers in making cider vinegar. 
TABLE IX.—INFLUENCE OF TEMPERATURE UPON FORMATION OF 
ACID FROM ALCOHOL. 
PERCENTAGE OF ALCOHOL PERCENTAGE OF ToTAL AcID 
In Ciper Kept. In CriperR Kept. 
AGE. a 
At lower At higher At lower At higher 
temperature. temperature. temperature. temperature, 
Months. Per ct. Per ct. Per ct. Per ct. 
Med-svateia oak GY ace Whole CMs L cinaetete 6.83 6.74 0.61 0.56 
Bistinvereis'w abarshere Byres elses aye 6.46 7 6.52 0.55 0.51 
ee or havaiahalorare avorerele Rae ate 6.00 6.30 0.69 0.69 
NO Se Sasi iaisyeram te oleseyits/saveas 5.54 5.79 0.79 L.J3 
Ue a epee RNA ti F fear si 4.85 S208 |e 1.40 3.82 
Pa Ee Al RID AOS OT 3.46 2.24 ART 6 Kheve 
DA Rela Eee G te NES roe 1.68 0.33 4.95 9.18 
7S ORT NE ESF 1.29 _ 0.00 — —2 
OA rare MAMI AAN Rice ate eat 0.00 0.00 5.55 9.23 
Bo aeiaic retorts Bes erate raids deece 0.00 0.00 6.48 10.30 
SORE Ts AMAL : e 0.00 0.00 6.88 10.84 
FE occas tnavacsamtarstniias siacarelaes 0.00 0.00 7.01 11.01 
ee 
