OCR
INDEX II 5 perspective of, 56; slightly in- | " Value” of water, 75. clined, 43. Vertical lines of image, persist. Sunset colours in rippled water, ence of in rippled water, 44, 50, 90, 105. 52. Sun-streak, 37; disappearance of | Vision, angle of, 65, 71, 75, note, of, 38, 98. 81, QI. Swiss lakes, 69, 82, 85, 87, 94, 107. Young-Helmholtz theory of colour perception, ror. Threlfall, Prof. R., 84, 109.