127 
comparatively small amount of water on the keeping qualities of copra. 
As shown in the previous experiment, copra containing 4.76 per cent of 
moisture remains practically unchanged on standing under conditions 
which preclude the absorption of water, while that with 9.09 per cent 
produced 11.8 per cent free acid in two weeks. Between these two 
extremes come the two samples mentioned above, the one with 6 per cent 
of water increasing to 0.89 per cent and that with 7.8 per cent rising to 
3 per cent of free acid during a period of two months. 
EXPERIMENTS ON COPRA DRYING. 
Since the quick and thorough drying of copra has been shown to be 
of such vital importance in order to insure the production of a pure oil, 
an investigation of various methods of copra drying has been made, taking 
into consideration not only the processes common in these Islands but 
also those which are used in other countries. 
Sun drying.—As has been stated in the introduction to this. series of 
papers, the simplest and most primitive mode of drying copra is to 
expose the nuts, cut in halves, to the action of the sun during about five 
days. ‘This method, although it is a slow one, under favorable climatic 
conditions produces a very fair quality of copra. However, a sudden 
rainstorm or a succession of cloudy days is sufficient to start mold 
and bacterial growth, with the consequent deterioration of the copra. 
Considerable loss due to the attacks of insects and animals is also suffered 
during the long period of drying, and the finished product very seldom 
contains less than 9 per cent of moisture. 
Grill drying.—A much quicker method is the one carried out by ine 
the half nuts, face downward, on a bamboo grating placed over a slow 
fire of coconut husks. After being dried in this manner over night the 
nuts are removed from their shells and are then again placed over the 
fire, where they are allowed to remain for from four to five hours longer. 
This process, although it is cheap and comparatively rapid, has the 
disadvantage of yielding a dark-colored product which has a smoke-like 
taste and odor, and it also tends to form a hard, burnt coating over the 
surface of the nut while the inside is left in a comparatively moist state, 
a fact which is often taken advantage of by the small producers, who 
sell their copra by weight. Commercial copra prepared in this way 
contains from 9 to 13 per cent of moisture. 
Hot-air drying.—This method of desiccation has been used successfully 
for a long time in the preparation of coffee, cacao, dried fruits, ete., and 
is at present in quite extensive use for the making of copra in Ceylon,’ 
where it is said to give a very pure, light-colored product. The type of 
apparatus used in that island essentially consists of a large chamber filled 
with wire trays upon which the coconuts are placed and over which a 
* Tropical Agriculturalist, 23, No. 10, supplement. 
