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36 LIGHT AND WATER appearing at $, as far below the level of the water, O, as P is above it. Beyond X, at A, B, C, and D, P is seen by reflexion on the ear sides 7 of the waves’ and the image is /ifted above J, appearing at a, ő, c, and d, respectively; whilst at all points nearer than X, as E, F, G, etc., it is seen by SSE reflexion on the farther sides of the === waves, and the image is /owered to e, es J, g,ete. These points a, 4, c, d, A, e, —=-== J 2 etc., all lie in the vertical plane aes containing P and QO (ze. the plane of — ——— the paper) and when viewed from O —--— I _ will therefore all appear to lie in the == vertical line through P. Fig. 15 is SS S4=— intended to represent this view of the —————- _ waves in Fig. 14 as seen from 0), with the different images of P, namely, a, b, c, d, e, etc., formed in them. The farther sides of the waves are indicaESZE Z ted by deeper shading. (If the water ==—h=—= were still, the image of P would apSSE = pear at £.) As the waves advance ———— == towards one, the images follow one — another downwards in the vertical Fig. 15.Pandits line (or upwards, if the waves are wubess , 18. SN going from one). Zhus in the rippled ener zh water the combined effect of all the images of the luminous point P, formed by reflexion . ' The crests and troughs of the waves are marked by short ver. tical lines.
