62 
Fertilization and irrigation—In the case of the less permeable soils, 
artificial irrigation during the dry season would seem to be of the utmost 
importance, and any addition to the fertility of the- land, either in the 
form of manure or of a chemical fertilizer, would probably be repaid by 
an increased yield of fruit. For soils near the sea, under conditions such 
as exist at San Ramon, irrigation is of course unnecessary excepting in 
times of extreme drought, and fertilization would be of doubtful advan- 
tage, as the trees in such a location seem to be growing under the 
best conditions possible without any attention whatsoever. Fertilizing 
material in such localities would probably be leached out and carried into 
the sea before it could be of much value to the trees. 
THE NUT AND ITS OIL PRODUCTION. 
The analytical methods used in compiling the accompanying tables 
were as follows: The weights, in grams, of husk, nut minus husk, shell, 
and milk were determined directly. To avoid loss by evaporation the 
meat itself was not weighed but was assumed to be the difference between 
the weight of the whole nut (minus the husk) and the combined weights 
of shell and milk. 
Copra.—The meat from each nut was allowed to dry in the air over night, so 
as to assume a fairly constant weight, and was then weighed directly; 25 grams 
were then cut into fine pieces and dried to constant weight at 100° C. for the 
determination of anhydrous copra, the latter being ealeulated back to per cent 
in the fresh meat. To approximate the amount of commercial copra obtainable, 
an addition of about 10 per cent should be made because of the water ordinarily 
contained in this product, 
Oil—The anhydrous copra prepared at San Ramon was sealed in glass bottles 
and shipped to Manila for analysis, the majority of the oil determinations being 
made by Mr. George F. Richmond, of this laboratory. Before this time much 
work had been done in devising a method for the rapid and accurate estimation of 
oil in copra. It was found to be almost impossible to make a complete extraction 
by the ordinary method of cutting fine pieces and extracting with ether in a 
Soxhlet cone. Even after the apparatus had been running for forty hours, a 
small increase in weight was obtained by extracting for eight hours more. Grind- 
ing with sand and then extracting with ether produced some improvement. 
Extraction with hot chloroform alone took out a little more oil, but it was 
necessary to continue the operation for at least sixteen hours. The method finally 
used was as follows: 
A 2-gram sample was intimately ground with fine sand in a glass mortar, the 
mixture transferred to a Soxhlet cone, the mortar washed two or three times 
with fresh sand, and then finally wiped with fat-free cotton. The extraction with 
hot chloroform takes three hours. 
The chloroform is then distilled and the remaining oil dried to constant weight 
at 100° C. Experiment demonstrated that practically all the oil was extracted 
in two hours. The chloroform extract made in this way proved to be entirely 
soluble in absolute ether. The sand used was prepared from ordinary sea sand 
by taking all which went through a 30-mesh and which was retained on a 100- 
mesh sieve, heating this product for some time to destroy organic matter and 
then afterwards extracting with chloroform. 
