should show Rigel double; in earlier editions of his work he gave
2-3/4-inches as the necessary aperture. Smyth mentions Rigel as a test
for a 4-inch aperture, with powers of from 80 to 120. A 3-inch aperture,
however, will certainly show the companion. Rigel is an orange star, the
companion blue.

Turn next to [lambda] the northernmost of the set of three stars in the
head of Orion. This is a triple star, though an aperture of 3 inches
will show it only as a double. The components are 5" apart, the colours
pale white and violet. With the full powers of a 3-1/2-inch glass a
faint companion may be seen above [lambda].

The star [zeta], the lowest in the belt, may be tried with a 3-1/2-inch
glass. It is a close double, the components being nearly equal, and
about 2-1/2" apart (see Plate 3).

For a change we will now try our telescope on a nebula, selecting the
great nebula in the Sword. The place of this object is indicated in
Plate 2. There can be no difficulty in finding it since it is clearly
visible to the naked eye on a moonless night--the only sort of night on
which an observer would care to look at nebulæ. A low power should be
employed.

The nebula is shown in Plate 3 as I have seen it with a 3-inch aperture.
We see nothing of those complex streams of light which are portrayed in
the drawings of Herschel, Bond, and Lassell, but enough to excite our
interest and wonder. What is this marvellous light-cloud? One could
almost imagine that there was a strange prophetic meaning in the words
which have been translated "Canst thou loose the bands of Orion?"
Telescope after telescope had been turned on this wonderful object with