Abstract
The yield of oil was measured simultaneously with the micrometeorological observation in a geranium-garden of Hakata, Ehime Pref. on Aug. 16 and 17, 1958. The yield of oil of leaves was measured with a microstill, and the temperatures (air-., leaf-, and ground surface-temp.) were observed with a thermograph set near the plant (Table 1 & 2). The comparison of the daily fluctuation of percentage yield of oil with that of micrometeorological elements gives the followings (Fig. 2): (1) The percentage yield of oil increases with solar radiation, reaches the maximum at 18' o'clock, thereafter decreases remarkably, and reaches. the minimum next morning. (2) High air temperature and low humidity have a favourable influence on increasing the yield of oil. (3) The daily fluctuation of percentage yield of oil of young leaves is more remarkable than that of old leaves. This seems to be brought about chiefly by the high leaf-temperatures and a large amount of solar radiation in the crown of the plant.
