Oldal 102 [102]
OCR
56 LIGHT AND WATER excellent photographs of fishing smacks by Mr. C. E. Wanless show some beautiful and curious effects of foreground reflexions, and are of more value than many words in illustrating the play of the water, or as suggestions for the drawing of ripples. (Plates XXVI-XXXII, XXXVII.) NOTE ON THE PERSPECTIVE OF ELONGATED KEFLEXIONS. On page 36 we saw how the streak of light which appears in rippled water as the reflexion of a luminous point, such as a lamp, is formed by the light catching the surface of the water at different points which, neglecting the irregularities of the surface, may be said to lie on a straight line on the surface extending from a point vertically below the eye to a point vertically below the lamp. For example, the points A, B, C, D, E, F, etc. (Figs. 14 and 15) lie on sucha line. If several lamps are seen reflected side by side, the streaks of light on the surface of the water corresponding to them will evidently zo¢ be parallel, radiating as they do from the point below the eye. But these streaks of light regarded as lines de/ow the surface have been shown (page 36) to appear as vertical—and therefore parallel—lines. The question might therefore arise, should these streaks of light de drawn as vertical lines, or as lines radiating from the “Point of Station?” That the former is the correct answer is clear from a consideration of Fig. 14. Viewed from QO, the perspective representations of the points a, 6, c, d, e, etc. (z.e., their projections on to the picture plane), must lie in the same vertical line with that of P, as shown in Fig. 15. If there were a second luminous point alongside of P (Fig. 15) its images would in the same way arrange themselves in the vertical line through that point, and so on for any number of luminous points. Should further proof be required, it is given by the law of perspective that the vanishing point
