This will be understood from Fig. 48, in which LL is the lens of the camera, AB the breadth of the trunk or stem of a tree less than LL in width. Draw LA, LB, touching AB in the points A, B, and crossing at C. Objects behind AB, and placed within the angle ACB, will not have any images of them formed by the lens LL, because none of the rays which proceed from them can fall upon the lens, but objects placed within the angle ECF, however remote be their distance, will have images of them formed by the lens. If D, for example, be a leaf or a fruit, or a portion of a branch, the rays which it emits will fall upon the portions L_m_, L_n_ of the lens, determined by drawing D_m_, D_n_ touching AB, and an image of it will be formed in the centre of the photographic image of AB, as if AB were transparent. This image will be formed by all the portions of the surface of the lens on which the shadow of AB, formed by rays emanating from D, would not fall. If the object D is more remote, the shadow of AB will diminish in size, and the image of the object will be formed by a greater portion of the lens. If the sun were to be in the direction MN, his image would appear in the centre of the trunk or stem, corresponding to AB, Fig. 49. [Illustration: FIG. 49.] If the stem occupies any other position, _ab_, Fig. 48, in the landscape, objects, such as _d_, within the angle _ecf_, will have images of them formed within the corresponding portion of the trunk or stem. Hence, if AB, Fig. 49, represents the shadow of the stem across the lens LL, the image of any object, which if luminous would give this shadow, will be formed within the photographic image of the stem, and as every part of it may have branches, or leaves, or fruit behind it, its photographs will be filled with their pictures, which will have the same distinctness as other equidistant parts of the landscape. These observations are applicable to the limbs and slender parts of animate and inanimate figures, when they are of a less size than the lens with which their photograph is taken. They will be transparent to all objects behind them, and their true forms and shades cannot be taken with the cameras now in use.[60]