Ocular refraction and the shadow test . Figure I i mage by a c<object, L M; imaije. idary ax the object being situated beyond tlie ce; centre of curvature, C; principle foe?s, L H and M G. Figure 20 represents an object L M so placed with regard to themirror that no ray passes from it along the principle axis. To locatethe image in such cases draw the path of a ray from the point L par-allel to the principle axis and incident at F, from F it is reflected. Position of image of obj through the principle focus; another ray from the same point L form-ing a secondary axis L E. The conjugate foci
Ocular refraction and the shadow test . Figure I i mage by a c<object, L M; imaije. idary ax the object being situated beyond tlie ce; centre of curvature, C; principle foe?s, L H and M G. Figure 20 represents an object L M so placed with regard to themirror that no ray passes from it along the principle axis. To locatethe image in such cases draw the path of a ray from the point L par-allel to the principle axis and incident at F, from F it is reflected. Position of image of obj through the principle focus; another ray from the same point L form-ing a secondary axis L E. The conjugate foci of E L and F P lo-cates the image of the point L at L; in the same manner locate theimage of M at M, etc. When the object lies wholly to one side of theprinciple axis the image is upon the other. O C U L A K R E F R A C T I O N. In figure 21 the object L M is situated between the principlefocus P and the vertex D An incident ray L E parallel to theprinciple axis C D is reflected through the principle focus P; a second-ary axis C L meets A B at G and a ray from L to G is reflectedthrough C; the reflected rays G C and E P are divergent and, there-fore, cannot meet; they have but a virtual focus which is located byextending them back of the mirror where they meet at the point L;the point M is found in the same way, and L M represents the vir-tual image of L M. Figure 22 shows at a glance the characteristics of images formedof objects in different posit
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Keywords: ., bookcentury1900, bookdecade1900, bookidocularrefrac, bookyear1903
