ading of the indexgives the position of the mirror. At E is a second piece ofplane glass, only one half of which is silvered. The plane of thisglass is parallel to AB, so that when the arm D is at B andthe circle reads zero, the two mirrors are parallel. A smalltelescope T is fixed to the arm AB… … . 118. line AE and its axis ET are equally inclined to the mirror E.Hence light incident along AE is reflected into the telescope.To use the instrument it is held in the left hand so that itsplane is parallel to that through the two objects Q and P, andthe telescope is pointed so as to view Q…
Heat · Light
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