21,1 Cole: Manufacture of Industrial Alcohol 43 
sucrose and the alcoholic, acetic, and other fermentations begins 
almost immediately after the sap drops from the stem into 
the tuquil under ordinary local conditions of collection. When 
the sap arrives at the distillery the inversion is complete and 
the alcoholic fermentation has begun and is sometimes com- 
pleted. The juice is now milky in appearance and covered by 
a thick layer of foam. When the sap is collected in clean vessels 
the inversion does not begin for four or five hours. A white 
flocculent precipitate is slowly formed. The inversion of the 
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TIME IN DAYS. 
Fie. 2. Sap flow of nipa palm, average of six trees during one season. 
sugar begins at the same time. Gibbs has shown that a zymogen 
present in solution in the sap causes the separation of a white 
flocculent invertase which rapidly attacks the sucrose present. 
He found that if clean tuquils are used and limed with thick 
lime cream, the sap collected in them will remain unchanged 
for more than ten days. 
The rate of inversion of the sugar and the rate of formation 
of alcohol and acid are well brought out in fig. 3. 
