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voted his time to the study of divinity, with those celebrated theologists, Gregory Nazianzen, Epiphanius, and Didymus. To complete his studies, he ap. plied himself very closely to the Hebrew language, in which he was instructed by the celebrated Barraban, a Jewish Rabbi, and spent most of his time afterwards in a monastery at Bethlehem. In ihis solitary retirement be translated the Old Testament into Latin; the same version now styled the Vulgate, and the only one used or allowed by the Romish church. He died in the eightieth year of his age, A.D. 422.
Astronomical Occurrences. On the Nature and Position of the fixed Stars. : We shall, in this paper, detail some of the theories of Mr. Michell and Dr. Herschel concerning the nature and position of the fixed stars. · The great number of stars,' says Mr. Michell, that have been discovered to be double, triple, &c. by Mr. (now Dr») Herschel, if we apply the doctrine of chances, as I have heretofore done, in my inquiry into the probable parallax, &c. of the fixed stars, published in the Philosophical Transactions for the Year 1767, cannot leave a doubt, with any one who is properly acquainted with the force of these arguments, that by far the greatest part, if not all of them, are systems of stars so near each other, as probably to be liable to be affected sensibly by their mutual gravitation ; and it is therefore not unlikely that the periods of the revolutions of some of these about their principal, the smaller ones being, upon this hypothesis, to be considered as satellites to the other, may some time or other be discovered.' Having then shown in what manner the magnitude of a fixed star, if its density were known, would affect the velocity of its light, he concludes, that if the semidiameter of a sphere of the same density with the Sun were to’exceed his in the proportion of 500 to 1, a body falling from an infinite
height towards it, or moving in a parabolic curve at its surface, would have acquired a greater velocity -than that of light; and consequently, supposing light to be attracted by the same force, in proportion to its vis inertiæ with other bodies, all light emitted from such a body would be made to return towards it by its own proper gravity. But if the semidiameter of a sphere of the same density with the Sun was of any other size less than 497 times that of the Sun, though the velocity of light emitted by such a body would never be wholly destroyed, yet it would always suffer some diminution, more or less, according to the magnitude of the sphere. After proceeding farther in his calculations, in order to find the diameter and distance of any star, he proceeds :- According to M. Bouguer, the brightness of the Sun exceeds that of a wax candle in no less proportion than that of 8000 to l. If, therefore, the brightness of any of the fixed stars should not exceed that of our common candles, which, as being less luminous than wax, we will suppose to be, only totooth part as bright as the Sun, such a star would not be visible at more than toth part of the distance at which it would be seen if it were as bright as the Sun. Now because the Sun would still, I apprehend, appear as bright and luminous as the star Sirius, if removed 400,000 times his present distance, such a body, if no brighter than our common candles, would appear equally luminous with that star at 400 times the distance of the Sun; and we ought then to be able, with the best telescopes, to distinguish some sensible apparent diameter of it: but the apparent diameters of the stars of lesser magnitudes would still be too small to be distinguishable even with our best telescopes, unless they were a good deal less luminous, which, however, may possibly be the case with some of them : for though we have, indeed, very slight grounds to go on with regard to the specific brightness of the fixed stars, compared with that of the Sun at present, and can, therefore, only
form very uncertain and random conjectures concerning it; yet, from the infinite variety which we find in the works of the creation, it is not unreasonable to suspect, that very possibly some of the fixed stars may have so little natural brightness in proportion to their magnitude, as to admit of their diameters having some sensible apparent size when they shall come to be more carefully examined, and with larger and better telescopes than have hitherto been in use.... .
With respect to the Sun, we know his whole surface is extremely luminous, a very small and tempo, rary interruption sometimes, from a few spots, ex: cepted. This universal and excessive brightness of the whole surface is probably owing to an atmosphere, which being luminous throughout, and in some measure also transparent, the light proceeding from a considerable depth of it all arrives at the eye, in the same manner as the light of a great number of candles would do if they were placed one behind another, and their flames were sufficiently transparent to permit the light of the more distant ones to pass through those that were nearer without interruption. ..
How far the same constitution may take place in the fixed stars we do not know ; it may in some, but, with regard to others, it does not seem to be the case, particularly in those which are, in some degree, periodically more or less luminous'; and also in those which have sometimes appeared and disappeared : and if those conjectures are well founded, which have been formed by some philosophers concerning stars of this kind, that they are not wholly luminous, or at Jeast not constantly so, but that all, or by far the greatest part, of their surfaces : is subject to considerable changes, sometimes becoming luminous, at others extinguished; it is among stars of this sort that we are most likely to meet with instances of a sensible apparent diameter, their light being much more likely not to be so great in proportion as that of the Sun, which, if removed to 400,000 times his pre. sent distance, would still appear, I apprehend, as bright as Sirius, as have been observed; whereas it is hardly to be expected, with any telescope whatever, that we should ever be able to distinguish a well defined disk of any body of the same size with the Sun, at more than 10,000 times his present distance.'
Hence the greatest distance at which it would be possible to distinguish any sensible apparent diameter of a body as dense as the Sun, cannot well greatly exceed five hundred times ten thousand ; that is five million times the distance of the Sun-; for if the dia meter of such a body were not less than 500 times that of the Sun, its light, as has been shown, could never arrive at us.
Dr. Herschel, improving on Mr. Michell's idea of the fixed stars being collected into groups, and as: sisted by his own observations with telescopes of extraordinary powers, has suggested a theory concerning the construction of the universe, which was as ingenious as it was new. It had been the opinion of former astronomers, that our Sun, besides occupying the centre of the system which properly belongs to him, occupied also the centre of the universe; but Dr. Herschel is of a different opinion. Hitherto,' says he, the sidereal heavens hạve (not inadequately for the purpose designed) been represented by the concave surface of a sphere, in the centre of which the eye of the observer might be supposed to be placed. It is true, the various magnitudes of the fixed stars even then plainly suggested to us, and would have better suited, the idea of an expanded firmament of three dimensions ; but the observations upon which I am now going to enter, still farther illustrate and enforce the necessity of considering the heavens in this point of view. In future, therefore, we shall look upon those regions into which we may now penetrate by means of large telescopes, as a na turalist regards a rich extent of ground or chain of mountains containing strata variously inclined and
directed, as well as consisting of very different materials. The surface of a globe, therefore, will but ill delineate the interior parts of the heavens.''
The Sun's rising and setting for certain days this month will be as follow; viz. on the
1st, Sun rises 14 m. past 5. Sun sets 46 m. past 6. 11th, - - 33 · - 5. . - - - 26 - - 6
21st, - - - 53 - - - 5. • - - 7 - - 6 :. Equation of Time.-The following table will point out what is to be subtracted from apparent time, to obtain equal or true time for every 5th day of the month :
Thursday, Sept. 1, from the time on the dial SUBTRACT
The Sun enters the sign Libra on the 23ů, at 55 m. past 4 in the afternoon.
The Moon enters its last quarter on the 7th day of Sept. at 34 m. past 5. The change, or New Moon, occurs at 18 m. past 11 at night on the 13th., This enters its first quarter on the 21st, at 41 m. past noon, and the Moon is at its full at 53 m. past 11 in the forenoon of the 29th.
The time of the Moon's rising for the five first days after the time of being full on the 30th of August, referred to before, will be as follows: August 31st, - • • 31 m, after 7
: , r.
Sept. 1st, - '• • .52 - . 7 . is)!!!
| 2d, • •. 13• .' • 8 ; .!
... 4th, - - • • 57 - . -8 The planet Venus will eclipse, on the 15th, the star e N; · and on the 20th, she will eclipse e si On the 27th, the Moon will eclipse the star marked 3 at home and The immersion will occur at 55 m. past 7 in the evening, and the emersion at past 8; the star; in both cases, being 13'} north of the Moon's