spectroscope for solar observation, [182].

The Telescope:

refractors and reflectors, [2], [8].

eyepieces, [6], [9], [10].

aberration (chromatic), 6;

(spherical), [6], [17].

achromatic telescopes, how made, [7].

object glass, [8].

magnifying power, [11].

mountings, [12].