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. 1877Crookes in Proc.Roy.Soc.No. 180.