otheoscope

\\ˈōthēəˌskōp\ noun

Etymology: Greek ōthein to push + English -o- + -scope — more at endosmosis

: an instrument for exhibiting the pressure exerted by light or other radiation in an exhausted vessel — compare radiometer

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otheoscope

(ˈəʊθiːəʊskəʊp)

[f. Gr. ὠθεῖν to push + -σκοπος observing, -scope.]

A modification of the radiometer, devised by Sir W. Crookes, in which the black or driving surface is stationary, while the cooling surface is movable.

Crookes in Proc. Roy. Soc. No. 180.