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 ASTRO N O M Y. 445 that there are at leafl 21'comets belonging to ourfyftem, the wifdom, fymmetry, and beauty of the creation ; which moving in all forts of dire&ions ; and all thofe which have is more plainly to be obferved in their extenfive tour j been obferved, have moved through the etherial regions through the heavens, than in our more confined circuit. and the orbits of the planets without fuffering the lead If farther conjeifture is permitted, may we not fuppofe fenfible refiftance in their motions; which plainly proves them inftrumental in recruiting the expanded fuel of that the planets do not move in folid orbs. Of all the the fun, and fupplying the exhaufted moifture of the comets, the periods of the above mentioned three only planets ? However difficult it may be, circumftanced as are known with^any degree of certainty. The firft of we are, to find out their particular deftination, this is an thefe comets appeared in the years 1531, 1607, and undoubted truth, that where-ever the Deity exerts his 1682; was expeded to appear again in the year 1758, power, there he alfo manifefts his wifdom and goodnefs. and every 75th year afterwards. The fecond of them The folar fyftem here defcribed is not a late invenappeared in 1532 and 1661, and maybe expected to re- tion, for it was known and taught by the wife Samian turn in 1789, and every 129th year afterwards. The philofopher Pythagoras, and others among the ancients; third, having laft appeared in 1680, and its period being but in latter times was loft, till the 15th century, when no lefs than 575 years, cannot return until the year 2225. it was again reftored by the famous Polifh philofopher, This comet, at its greateft diftance, is about 11 thoufand Nicholas Copernicus, who was born at Thorn in the year two hundred millions of miles from the fun; and at its 1473. In this he was followed by the greateft matheleaft diftance from the fun’s centre, which is 490,000 maticians and philofophers that have fince lived ; as miles, is within lefs than a third part of the fun’s femi- Kepler, Galileo, Defcartes, Gaffendus, and Sir Ifaac diameter from his furface. In that part of its orbit Newton; the laft of whom has eftabfifhed this fyftem which is neareft the fun, it flies with the amazing fwift- on fucli a foundation of mathematical and phyfical denefs of 880,000 miles in an hour; and the fun, as feen monftration, as can never be fhaken. from it, appears an hundred degrees in breadth, confe- In the Ptolemean fyftem, the earth was fuppofed to be quently 40 thoufand times as large as he appears to us. fixed in th ecentre-of the univerfe ; and that the Moon, The aftonifhing length that this comet runs out into Mercury, Venus, the Sun, Mars, Jupiter, and Saturn, empty fpace, fuggefts to our minds an idea of the vaft moved round the earth : Above the planets this hypodiftance between the fun and the neareft fixed ftars ; of thefis placed the firmament of ftars, and then the two of whofe attractions all the comets muft keep clear to cryftalline fpheres; all which were included in and receireturn periodically, and gO found the fun; and it Ihews us ved motion from the priinum mobile, which conftantly alfo, that the* neareft ftars," which are probably thofe revolved about the earth in 24 hours from eaft to weft. that feem the largeft, are as big as our fun, and of the But as this rude fcheme was found incapable to ftandthe fame nature with him ; otherwife they could not appear teft of art and obfervation, it was foon rejected by all fo large and bright to us as they do at fuch an immenfe true philofophers. diftance. The Tychonic fyftem fucceeded the Ptolemean, but The extreme heat, the denfe atmofphere, the grofs was never fo generally received. In this the earth was vapours, the chaotic ftate of the comets, feem at firft fuppofed to ftand ftill in the centre of the univerfe or firlight to indicate them altogether unfit for the purpofes mament of ftars, and the fun to revolve about it every 2 4 of animal life, and a moft miferable habitation for ra- hours; the planets. Mercury, Venus, Mars, Jupiter, tional beings; and therefore fome are of opinion that and Saturn, going round the fun in' the times already they are fo many hells for tomenting the damned with mentioned. But fome of Tycho’s difciples fuppofed the perpetual viciffitndes of heat and cold. But when we earth to have a diurnal motion round its axis, and the confider, on the other hand, the' infinite power 'and fun, with all the above planets, to go round the earth in goodnefs of the Deity, the latter inclining, and the a year; the planets moving round the fun in the forefaid former enabling liim to make creatures fuited to all times. This hypothefis, being partly true, apd partly' ftates and circumftances; that matter exifts only for the falfe, was embraced by few ; and foon gave way to the fake of intelligent beings ; and that where-ever we find only true and rational fcheme, reftored by Copernicus, it, we always find it pregnant with life, or neceflarily and demonftrated by Sir Ifaac Newton. fubfervient thereto; the numberlefs fpecies, the aftonifliing diverfity of animals in earth, air, v/ater, and e- Chap. III. The Phenomena of the Heavens ven on other animals; every blade of grafs, every leaf, as feen from different Parts of the Earth. every fluid fwarming with life; and every one of thefe enjoying ftich gratifications as the nature and ftate of each requires : When we reflect moreover, that fome We are kept to the earth’s furface on all fides by the centuries ago, till experience undeceived us, a great part power of its Central attradHon ; which, laying hold of all of the earth was judged uninhabitable, the torrid zone bodies according to their denfities or quantities of matter, by reafon of exceflive heat, and the frigid zones be- without regard to their bulks, conftitutes what we call Caufe of their intolerable cold ; it feems highly pro- their weight. ■ And having the fky over our beads, go bable, that fuch numerous and large mafles of durable where we will, and our feet towards the centre of the matter as the comets are, however unlike they be to our earth, we call it up over our heads, and under our earth, are not deftitute of beings capable of contempla- feet: Although the fame right line which is do-wn to us, ting with wonder, and acknowledging with ‘gratitude, if continued through, and beyond tfie oppofite fide of the Vol. I. Numb. 19. 3 5U earth.