atmidometer

from The Collaborative International Dictionary of English v.0.48

Atmidometer \At`mi*dom"e*ter\, n. [Gr. ?, ?, smoke, vapor +
   -meter; cf. F. atmidom[`e]tre.]
   An instrument for measuring the evaporation from water, ice,
   or snow. --Brande & C.
   [1913 Webster]