38 
If the tree produces but 20 nuts per annum, which is more than the 
recent average at San Ramon, the loss of mineral matter in these is 
1,140 grams and the total loss in leaves and nuts 5,220 grams. If this 
were absorbed in 10,220 liters of water the concentration would be 0.051 
per cent. This is considerably above the average concentration to be 
found in ground water, as determined by analyses from water in wells 
and springs, but as a general proposition the water in intimate contact 
with the ground particles, and, when there is but little water in the soil, 
all of it, will be more concentrated than that which will run freely from 
wetter ground; and the valuable mineral food of plants is absorbed from 
such dilute solutions in greater proportion than is the water in which it is 
dissolved. 
Effect of drought.—The season during which I carried on my work at 
San Ramon was characterized by extreme dryness, and this condition has 
interfered with my study of the plant’s normal physiology, but at the 
same time it has given me an opportunity to observe the injury done by 
the abnormal conditions. The following table contains my measure- 
ments of the rainfall for this year and Mr. Havice’s for the corresponding 
months a year ago: 
Relative 
Month. 1904-5. 1908-4. humidity, 
| 1904-5. 
mm. mm, | Per cent. 
| November 2.-...---—— (15-80) 91.5 | (1-30) 208 | 79.9 
| Deeember .-.--__.--.-- 2.5 260 79, 2 
a”. aaenneennenan 30 32 75, 65 | 
| WeGruUaly .n6-6065-5=-5. 1 431 72, 35 
| March -__-.-_--------- | | 232 75.48 | 
AONE oxccdecdewaccacuns 12.5 2 74.9 | 
| 
The third column gives the average relative humidity at or near the 
beach at 11.30 a. m. for November and at noon for the remaining months. 
Details as to the rainfall and humidity during my work are presented in 
the appendix to this paper. While the dryness of the air certainly has 
some direct effect on the coconut trees—for example, in influencing the 
movement of the hinge, without regard to how well the roots may have 
been supplied with water—I do not believe that serious damage is ever 
done to the tree except by the dryness of the ground. In other words, 
trees judiciously irrigated have nothing to fear from a drought, however 
severe, 
The cultivated part of the San Ramon farm is well supplied with 
ground water, which, as a rule, finds the surface through a number of 
large springs. ‘Tl'wo months after the drought began, some well-cultivated 
spots were still wet from below every morning. During November, 
December, and January, I frequently examined the young tips of roots, 
and through these months there was no important change in the condi- 
tion of the ground and accordingly none in the roots. After the latter 
