Figure 68 grating only become centers of wavelets because the incidentplane wavefronts bring the disturbance up to them. The ap-pearance of the mercury surface becomes like figure 68, whichis an instantaneous photograph. The heavy dark place of PLANE GRATING 125 irregular shape is the shadow of…
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Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
