Elements of natural philosophy (Volume 2-3) . Arrangement formoving thesemi-lenses; 200 NATURAL PHILOSOPHY. Illustration; Graduatedscrew head ; Spring; Value of oneentire turn ofscrew head j Value of onedivision. PIff. Method of usingthe dynameter; rangement indicated in the figure, wherein n is a right-handed screw with, say, fifty threads to an inch; n isa left-handed screw, with the same number of threadywhich works in theformer about a com-mon axis, and isfastened to theframe that carriesthe semi-lens screws, is ren-dered stationary as regards longitudinal motion, by a shoulder
Elements of natural philosophy (Volume 2-3) . Arrangement formoving thesemi-lenses; 200 NATURAL PHILOSOPHY. Illustration; Graduatedscrew head ; Spring; Value of oneentire turn ofscrew head j Value of onedivision. PIff. Method of usingthe dynameter; rangement indicated in the figure, wherein n is a right-handed screw with, say, fifty threads to an inch; n isa left-handed screw, with the same number of threadywhich works in theformer about a com-mon axis, and isfastened to theframe that carriesthe semi-lens screws, is ren-dered stationary as regards longitudinal motion, by a shoulder that turnsfreely within the top of the frame $ T at r, and worksin a nut at F, connected with a frame that carries thesemi-lens E; this screw is provided with a large cir-cular head X Y, graduated into one hundred equalparts, which may be read by means of an index at Xor I7, on the frame of the instrument. At £, is a springthat serves to press the frames against their respectivescrews, to prevent loss of motion when a change ofdirection in turning takes place. When the graduated head is turned once round to theright, the semi-lens Ef, is drawn up ^ of an inch, whilethe semi-lens jE7, is thrust in an opposite direct
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Keywords: ., bookcentury1800, booksubjectmechanics, booksubjectopticsandphoto
