Abstract
A pair of Hirata's filter paper evaporimers, consisted of one black and one white, are utilized as the instrument.
The difference between evaporation from the black and the white, is indicated as a relative measure of effective radiation.
The empirical formula is shown as follows: Y=119.815+20.557X, where Y is inte-grated intensity of radiation in g•cal/cm2 and X is the difference of evaporation in gram.
