COMPARISON OF SEVERAL DIFFERENT ATMOMETER ASSEMBLIES

Abstract

Five different Bellani-type atmometers were field rested in pairs. Each design satisfied the ten basic requirements for a practical atmometer, but failed to satisfy all of ten secondary requisites of a technical nature. However, the carborundum block atmometer met all except one, namely that readings from it must be adjusted because u uses an alcohol-water mixture which does not give a true measure of the evaporation of water. The advantages of the carborundum block are: it is easy to prime and fill, it is free of most of the operational defects that beset other designs, it can withstand temperatures down to −12 °C, different instruments are highly consistent in performance, and the evaporating heads do not need calibrating.