The clinical use of prisms; and the decentering of lenses (1893)
Maddox, Ernest Edmund, 1860-1933 · Bristol : J. Wright ; London : Simpkin, Marshall, Hamilton, Kent · leaf 18
vely. Trial cases usedgenerally to be provided with a series of prisms, THEIR GEOMETRICAL PROPERTIES. marked in this way, from i° or 23 up to 12° or 240.The angle of refraction is the one item the opticianneeds to know in order to grind a prism. He firstsets a pair of compasses so that their legs… … ...M Fig. 2.—Prism Measure: the index points to the requiredangle when the teeth at its foot are pressed upon the prism. may simply call it, the angle of a prism, wemay resort to the same manoeuvre, and after grasp-ing the prism between a pair of compasses, measure 4 PRISMS. the angle they include…
Lenses
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