hygrometrical

from The Collaborative International Dictionary of English v.0.48

Hygrometric \Hy`gro*met"ric\, Hygrometrical \Hy`gro*met"ric*al\,
   a. [Cf. F. hygrom['e]trique.]
   1. Of or pertaining to hygrometry; made with, or according
      to, the hygrometer; as, hygrometric observations.
      [1913 Webster]

   2. Readily absorbing and retaining moisture; as, hygrometric
      substances, like potash.
      [1913 Webster]