Pyr-hē'li-ŏm'e-ter, n.
n. [Gr. πῦρ, fire, ἥλιος, sun, and μέτρον, measure.] An instrument for measuring the direct heating effect of the sun’s rays; an actinometer.
n. [Gr. πῦρ, fire, ἥλιος, sun, and μέτρον, measure.] An instrument for measuring the direct heating effect of the sun’s rays; an actinometer.