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 nebulae.  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 the hope of resolving its light into stars.  But it proved intractable to Herschel’s great reflector, to Lassell’s 2-feet reflector, to Lord Rosse’s 3-feet reflector, and even partially to the great 6-feet reflector.  Then we hear of its supposed resolution into stars, Lord Rosse himself writing to Professor Nichol, in 1846, “I may safely say there can be little, if any, doubt as to the resolvability of the nebula;—­all about the trapezium is a mass of stars, the rest of the nebula also abounding with stars, and exhibiting the characteristics of resolvability strongly marked.”

It was decided, therefore, that assuredly the great nebula is a congeries of stars, and not a mass of nebulous matter as had been surmised by Sir W. Herschel.  And therefore astronomers were not a little surprised when it was proved by Mr. Huggins’ spectrum-analysis that the nebula consists of gaseous matter.  How widely extended this gaseous universe may be we cannot say.  The general opinion is that the nebulae are removed far beyond the fixed stars.  If this were so, the dimensions of the Orion nebula would be indeed enormous, far larger probably than those of the whole system whereof our sun is a member.  I believe this view is founded on insufficient evidence, but this would not be the place to discuss the subject.  I shall merely point out that the nebula occurs in a region rich in stars, and if it is not, like the great nebula in Argo, clustered around a remarkable star, it is found associated in a manner which I cannot look upon as accidental with a set of small-magnitude stars, and notably with the trapezium which surrounds that very remarkable black gap within the nebula.  The fact that the nebula shares the proper motion of the trapezium appears inexplicable if the nebula is really far out in space beyond the trapezium.  A very small proper motion of the trapezium (alone) would long since have destroyed the remarkable agreement in the position of the dark gap and the trapezium which has been noticed for so many years.