The man of science himself is fonder of glory, and vain-An eye well practised in nature, a spirit bounded and poor.
That Hevelius, 'the star-cataloguer,' should have failed to detect the Orion nebula is far less remarkable; for Hevelius objected to the use of telescopes in the work of cataloguing stars. He determined the position of each star by looking at the star through minute holes or pinnules, at the ends of a long rod attached to an instrument resembling the quadrant.
The actual discoverer of the great nebula was Huy-ghens, in 1656. The description he gives of the discovery is so animated and interesting, that we shall translate it at length. He says:
'While I was observing the variable belts of Jupiter, a dark band across the centre of Mars, and some indistinct phenomena on his disc, I detected among the fixed stars an appearance resembling nothing which had ever been seen before, so far as I am aware. This phenomenon can only be seen with large telescopes such as I myself make use of. Astronomers reckon that there are three stars in the sword of Orion, which lie very close to each other. But as I was looking, in the year 1656, through my 23-feet telescope, at the middle of the sword, I saw, in place of one star, no less than twelve stars-which indeed is no unusual occurrence with powerful telescopes. Three of these stars seemed to be almost in contact, and with these were four others which shone as through a haze, so that the space around shone much more brightly than the rest of the sky. And as the heavens were serene and appeared very dark, there seemed to be a gap in this part, through which a view was disclosed of brighter heavens beyond. All this I have continued to see up to the present time [the work in which these remarks appear-the Systema Satumium-was published in 1659], so that this singular object, whatever it is, may be inferred to remain constantly in that part of the sky. I certainly have never seen anything resembling it in any other of the fixed stars. For other objects once thought to be nebulous, and the Milky Way itself, show no mistiness when looked at through telescopes, nor are they anything but congeries of stars thickly clustered together.'
Huyghens does not seem to have noticed that the space between the three stars he described as close together is perfectly free from nebulous light - insomuch that if the nebula itself is rightly compared to a gap in the darker heavens, this spot resembles a gap within the nebula. And indeed, it is not uninteresting to notice how comparatively inefficient was Huyghens' telescope, though it was nearly eight yards in focal length. A good achromatic telescope two feet long would reveal more than Huyghens was able to detect with his unwieldy instrument.
Dominic Cassini soon after discovered a fourth star near the three seen by Huyghens. The four form the celebrated trapezium, an object interesting to the possessors of moderately good telescopes, and which has also been a subject of close investigation by professed astronomers. Besides the four stars seen by Cassini, there have been found five minute stars within and around the trapezium. These tiny objects seem to shine with variable brilliancy; for sometimes one will surpass the rest, while at others it will be almost invisible.
After Cassini's discovery, pictures were made of the great nebula by Picard, Le Gentil, and Messier. These present no features of special interest. It is as we approach the present time, and find the great nebula the centre of quite a little warfare among astronomers -now claimed as an ally by one party, now by their opponents-that we begin to attach an almost romantic interest to the investigation of this remarkable object.
In the year 1811, Sir W. Herschel announced that he had (as he supposed) detected changes in the Orion nebula. The announcement appeared in connection with a very remarkable theory respecting nebulas generally-Herschel's celebrated hypothesis of the conversion of some nebulas into stars. The astronomical world now heard for the first time of that self-luminous nebulous matter, distributed in a highly attenuated form throughout the celestial regions, which Herschel looked upon as the material from which the stars have been originally formed. There is an allusion to this theory in those words of the Princess Ida :
There sinks the nebulous star we call the Sun, If that hypothesis of theirs be sound.
And in the teaching of 'comely Psyche':
This world was once a fluid haze of light, Till toward the centre set the starry tides, And eddied into suns, that wheeling cast The planets.
Few theories have met with a stranger fate. Received respectfully at first on the authority of the great astronomer who propounded it-then in the zenith of his fame-the theory gradually found a place in nearly all astronomical works. But, in the words of a distinguished living astronomer, 'The bold hypothesis did not receive that confirmation from the labours of subsequent inquirers which is so remarkable in the case of many of Herschel's other speculations.' It came to pass at length that the theory was looked upon by nearly all English astronomers as wholly untenable. In Germany it was never abandoned, however, and a great modern discovery has suddenly brought it into general favour, and has in this, as in so many other instances, vindicated Herschel's claim to be looked upon as the most clear-sighted, as well as the boldest and most original of astronomical theorisers.
Herschel had pointed out various circumstances which, in his opinion, justified a belief in the existence of a nebulous substance-fire-mist or star-mist, as it-has been termed - throughout interstellar space. He had discovered and observed several thousand nebulae, and he considered that amongst these he could detect traces of progressive development. Some nebulas were, he supposed, comparatively young; they showed no signs of systematic aggregation or of central condensation. In some nebulas he traced the approach towards the formation of subordinate centres of attraction; while in others, again, a single centre began to be noticeable. He showed the various steps by which aggregation of the former kind might be supposed to result in the formation of star-clusters, and condensation of the latter kind into the formation of conspicuous single stars.