The rate of evaporation from different types of pans varies widely and before the evaporation data can be used in estimating the loss from large bodies of water, it is necessary to know the ratio between the evaporation from the type of pan used and that from a large water surface, or the relation between the evaporation from the pan and some pan for which the ratio of the evaporation to that from a large water surface is known. A summary of the results of the available records, where a comparison has been made between the evaporation from different types of pans or between the evaporation from a pan and a large water surface under similar conditions, is given in this paper, together with recommendations as to the best types of pan to use under different conditions, and the procedure to be followed in taking the observations.