Light visible and invisible : a series of lectures delivered at the Royal Institution of Great Britain, at Christmas, 1896 (1897)
Thompson, Silvanus Phillips, 1851-1916, Royal Institution of Great Britain · New York : Macmillan · leaf 220
mpared with the spectrum thatwould be produced by the useof a prism of glass or quartz ofthe same size. We might have used as anexploring apparatus, instead ofour thermopile, another instru-ment, the radiometer (Fig. 110).Rather more than twenty yearsago the celebrated chemistCrookes made the… … 200 LIGHT LECT. vacuum, the vanes of the mill are driven round.Apparently the blackened vane of the mill tends toretreat from the light. Why, we must presently con-sider. My present point is that it is possible to usethis apparent repulsion to measure the intensity of theradiation that falls upon…
Light · X-rays
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