42 The Philippine Journal of Science 1922 
8,700 liters per hectare. Less than one-third of this area was producing, 
partly from lack of labor and partly because the greater portion of the 
estate had not been made accessible to the distillery. The alcohol pro- 
duction from this yield was about 5 per cent. 
The atmospheric and climatic conditions affect the flow of sap. The 
natives working among the plants are positive that they can predict the 
approach of a storm by a sudden checking, in some cases amounting to 
almost a stoppage, in the flow, occurring about three days before the 
arrival of the typhoon. It is stated that after a temporary stoppage has 
been produced by meteorologic conditions an increased flow will start which 
will balance the period of inactivity. 
The seasonal variation in the composition of the fresh tuba must be 
slight, although when received at the distilleries the differences, both in 
quality and quantity, are very great. This is undoubtedly due to the fact 
that rains dilute the juice after it has flowed from the flower or fruit 
stalk. The gain in volume is balanced by the loss in sugar and alcoholic 
content. 
As a result of experimental work performed by Gibbs and 
others, an estimate of the yield of sap per plant per season is 
given as 43 liters, in a nipale cared for under average condi- 
tions according to present methods. This means an average 
daily yield of 0.58 liter and a total yield of 87,000 liters per 
hectare per year. The average flow of sap during the season 
is well shown in fig. 2. 
The following data were obtained by Gibbs *‘ on six trees: 
Liters. 
Total flow from six trees 260.286 
Greatest total flow from a single tree 49.410 
Lowest total flow from a single tree 36.335 
Average seasonal flow per tree 43.381 
Average daily flow from six trees 3.470 
Greatest daily flow from one tree ‘ 1.770 
Average daily flow per tree : 0.579 
The composition of the sap—From analyses made by Mr. 
Francisco Agcaoili, of the Bureau of Science, the following is 
the composition of a good quality sap: 
Brix 17.0 
i ao 
Density Tp 1.020 
Total solids 18.00 
Ash 0.48 
Acidity Trace. 
Sucrose 17.00 
Reducing sugar Trace. 
An invertase proferment, or zymogen, also occurs in the sap. 
Changes in the composition of the sap—The inversion of the 
“Op. cit. 121. 
