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 43
at, being 26 LIGHT LECT. themselves now curved ripples with hollow wave-fronts,they converge inwards upon one another, and march backtoward the point F. A bit of the wave-front at Pmarches straight until it strikes the mirror at R. Theninstead of going on to Q it is reflected inward andtravels to… … Fig. 14. come. We have then learned that, for ripples at least,a concave mirror may produce a real convergence to apoint. Let us at once snow that the same thing can be donewith light-waves by using a concave silvered mirror. From my optical lantern, with its internal electriclamp, my assistant…
Light · X-rays
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