抄録
A new differential evaporation recorder is designed and constructed which records the amount of evaporation from alarge evaporating pan. Two weights are suspended respectively in the pan and in a non evaporating surface covered with oil, and their movements are mainly due to the differential effect of buoiancy exerted on them when the evaporation takes place, for the effect of thermal expansion of water acts at the same sime on the weights, and thus having no influences. The principle and the mechanism of the recorder is illustrated in figs. 1 and 2. The size of the weights (radius=3.3cm.) are determined taking into consideration the effect of the friction of the recording pen and is found to have sufficient magnitude. The magnification of the recorder is variable by changing the ratio of lengths of the pen-arm as 5:1, 10:1, and 25:1.
