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 191
d.A quartz lens placedjust above the jar(Fig. 102) serves toconcentrate the beaminto a sharp cone ofcolour. I take asecond jar filledsimply with diluteammonia-water, andproject the beamdown it. Then Isprinkle into thewater a few grainsof dry fluorescein. As they dissolve there descend tothe bottom… … Fig. iv THE INVISIBLE SPECTRUM 171 of the photography of the invisible. The inscriptionpainted on the white sheet was painted with a solutionof quinine. You shall see for yourselves the invisibleinscription; for I have only to cast upon it a beam ofultra-violet light to cause the parts painted with…
Light · X-rays
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