Methods of Measuring the Evaporation of Water from Animals

DURING the past five years this problem of the evaporation of water from animals has attracted considerable attention, particularly from entomologists. Considerable advances have been made, but when the technique of various workers is examined from a physical standpoint it is difficult to see how far laboratory results can be applied to ecological problems in the field. During the last two years this aspect of the subject has been considered, and it is the purpose of this paper to draw attention to the purely physical problems which lie at the base of any attempt to establish a relation between the loss of water from an animal and the evaporating power of the air. No attempt is made to give a comprehensive survey or criticism of the methods of other workers: the examples quoted have been chosen merely to illustrate the argument.