We ought not, however, to imagine, that all the fixed stars are thus number ed, and reduced to their respective places in the heavens, since their num ber continually increases, according to the goodness of the telescope, appearing millions beyond millions, till, by their im mense distance, they evade the sight, even though assisted by the best instru ments. The telescopical stars, with which Mr. Flameteed has enriched his catalogue, are only the more remarkable ones, whose longitudes and latitudes, or situations in the heavens, it was thought worth while to register and put down. Dr. Hook, with a telescope of twelve feet, saw 78 stars among the Pleiades ; and with a longer telescope still more ; and, in the single constellation of Orion, which, in Mr. Famsteed's catalogue, has but 80 stars, there have been seen 2000. We may therefore venture to pronounce the number of fixed stars, including the telescopic ones as well as those visible to the naked eye, to be infinitely great, far beyond what it is possible for the best as. tronomers to calculate, much less to re duce to order. But though the stars are certainly innumerable, yet those visible to the naked eye, in one hemisphere, sel dom exceed a thousand; which, perhaps, may appear strange, since, at first sight, their number seems immensely great : but this is only a deception of sight, aris ing from a confused and transient view for let a person single out a small portion of the heavens, and, after some attention to the situation of the more remarkable stars therein, begin to count, he will soon be surprised to find how few there are therein. However, even the number of stars visible to the naked eye, small as it. is in comparison with that of the teles copic ones, is far from being constant ; since, besides that the different states of the atmosphere render many of the less. er stars invisible, some stars have been observed to appear and disappear by turns; particularly one in the chair Cus. siopeia, in the year 1572, which for some time outshone the biggest of the fixed stars, and in sixteen months time, by de grees vanished quite away, and was never seen since : in the year 1640, the scholars of Kepler saw a star in the right leg of Serpentarius, which likewise gradually disappeared ; Fabricitts, in the year 1596, gives the first account of the stella mire, or wonderful star, in the neck of the whale ; which has been since found to appear and disappear periodi cally, its period being seven revolutions in six years, but is never quite extin guished. Several other new stars have been observed: as one by LieVelillS, in 1670, and another by Mr. Kircher, in 1689. These new stars are generally observed in the galaxy or milky way. See GaLsxr.
As to the causes of this appearing and disappearing of the fixed stars, Sir Isaac Newton conjectures, that as it is possible our sun may sometimes receive an addi. Lion of fuel by the falling of a comet into it ; so the sudden appearance of some stars, which formerly were not visi ble to us, may be owing to the falling of a comet upon them, and occasioning an un. common blaze and splendour for some time ; but that such as appear and dia. appear periodically, and increase by very slow degrees, seldom exceeding the stars of the third magnitude, may be such as, having large portions of their surfaces obscured by spots, may, by revolving round their axis like the sun, expose their lighter and darker parts to us suc cessively.
Nature and Distance of the fixed Stars. From the similitude there appears to be between them and the sun, it is generally supposed by philosophers, that they are not placed in the heavens by way of orna ment only, or to supply us with a faint light in the absence of the moon ; but that each of them is placed in the midst of a system of planetary worlds, and that it directs their motions, and supplies them with light and heat, in the same manner that the sun does the several bo dies of which our solar system is com posed; in short, that they are so many suns, which no doubt have planets mov ing regularly round them, though invisi ble to us. That this is not mere hypothe
sis, will appear from the following argu ments, drawn from the analogy they bear to our sun : The sun shines by its own native light, and so do the fixed stars; the sun, at the distance of the fixed stars, would appear no larger than a star ; none of our planets, at that distance, could be seen at all : is it not probable, therefore, that each of the fixed stars is a fixed sun, surrounded by a system of planets and comets, which may be again furnished with different numbers of satellites, or moons, though invisible to us ? Besides, as the number of stars is immensely great, dispersed through spaces of the universe far beyond the reach of the best tele scopes, and as God has made nothing in vain, it seems highly probable that they severally serve the purposes of light and heat for the planets of their systems; since nothing can be more absurd than to pretend that myriads of unseen stars were made to twinkle in the unknown regions of the universe.
That the fixed stars shine by their own light is thus proved : when viewed through a telescope, they appear only as mere lucid points, destitute of all sensi ble magnitude, and consequently must be at a vast distance ; because the satellites of Jupiter and Saturn, when viewed through a telescope, appear of very dis tinguishable magnitudes, and yet are in visible to the naked eye. Since, then, the fixed stars are at such a vast distance, that the best telescope has no power to magnify them, and nevertheless shine with a very bright and sparkling light, it is inferred that they must shine with their own proper and unborrowed light ; be cause, if their light was only borrowed, they would, like the satellites already mentioned, be invisible to the naked eye.
The celebrated Huygens found the brightest and largest, and consequently the nearest of the fired stars, viz. Sirius, or the Dog-star, to be in appearance 27,664 times less than the sun ; and since the distances of objects are greater as their apparent magnitudes are less, the Dog-star must be distant from our earth, 2,000,000,000,000, or above two millions of millions of English miles ; which is so very great, that a cannon-ball, continuing in the same velocity it acquires when immediately discharged at the mouth of the cannon, would spend al most seven hundred thousand years in passing through it ; and it is very proba ble that the fixed stars are equally dis tant from each other, as the nearest of them is from the sun; since, the better the telescopes we make use of, the more stars are seen. Hence it is very natural to conclude, that all the fixed stars are not placed at equal distances from us ; but that they are every where interspers ed at great distances beyond one another, throughout the universe ; and that, pro bably, the different appearances which they make, in point of splendour and magnitude, may be rather owing to their various distances from us, than to any real difference in their magnitudes.
From what has been said concerning the number, nature, and distance of the fixed stars, the hypothesis of a plurality of worlds, wherein each fixed star serves as a sun to a system of planets, seems ra tional, worthy aj)hilosopher, and greatly displays the wisdom, and redounds to the glory of the great Creator and Governor of the universe. Under the article Sex, will be mentioned some of the specula tions of Dr. Herschel.