Actinometer

[,ækti'nɒmitә]

(noun.) an instrument for measuring the intensity of electromagnetic radiation (usually by the photochemical effect).

Inputed by Emilia--From WordNet

(n.) An instrument for measuring the direct heating power of the sun's rays.

(n.) An instrument for measuring the actinic effect of rays of light.

Typed by Konrad

n. an instrument for measuring the heat-intensity of the sun's rays or the actinic effect of light-rays.

Typist: Xavier