Light; a course of experimental optics, chiefly with the lantern . 6d., and is mounted as in Fig. 9, the tube being fixedinto a triangular cast socket, or one made of sheet brassturned up ^ inch. Into this the end of the prism iscemented. Of course, such a prism is not optically faced, only polished like lustres j but it is good enoughfor most screen work. In the socket, Fig. 6, it can beset and turned to any angle horizontally; but another i6 LIGHT. [chap. socket should be provided, as in Fig. lo, bearing a pieceof brass, a b, at the end, in which is bored, perpendicularly,a hole of the regul
Light; a course of experimental optics, chiefly with the lantern . 6d., and is mounted as in Fig. 9, the tube being fixedinto a triangular cast socket, or one made of sheet brassturned up ^ inch. Into this the end of the prism iscemented. Of course, such a prism is not optically faced, only polished like lustres j but it is good enoughfor most screen work. In the socket, Fig. 6, it can beset and turned to any angle horizontally; but another i6 LIGHT. [chap. socket should be provided, as in Fig. lo, bearing a pieceof brass, a b, at the end, in which is bored, perpendicularly,a hole of the regular socket gauge. In this the prism canbe turned to any angle vertically. For spectrum work a prism bottle filled with bisulphideof carbon is, however, far to be preferred, giving nearlydouble the dispersion of any ordinary glass prism. Sucha prism can, however, only be used vertically, and a glassone is handy for some other positions sometimes necessary. These fittings are recommended because they can beadjusted in work with such ease, precision, and.
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Keywords: ., bookcentury1800, bookdecade1880, bookidcu3192403121, bookyear1882
