Discoveries and inventions of the nineteenth century (1905)
Routledge, Robert · London : G. Routledge and Sons · leaf 518
rcumstances the observer may see the light at the back of the eye,but he will not be able to distinguish anything clearly, because his own eyecannot accommodate itself so as to bring to a focus the rays coming fromthe retina of the other, since these rays are refracted by the media throughwhich… … FiG. 241.—Ruet^s Ophthalmoscope. stitute the instrument called \}a& ophthalmoscope {o4>da.\txo% the eye) of whichthere are many forms, but all constructed on the principle just indicated.This principle was first pointed out by Helmholtz, who described the firstophthalmoscope in 1851. Ruetes…
Inventions
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