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ASTRINGENT, in chemistry, the substance, existing chieflyin nut-galls, the bark of some trees, and in various plants, whichcorrugates the tongue when tasted, gives a sensation of roughnessand harshness to the palate, aad produces a contraction of animaljelly. It is now called Tannin, which see.
ASTROGNOS1A, [from and yiwus-xw, I know,] the artof knowing the fixed stars, their names, ranks, situations in theconstellations, and the like. See Astronomy .
ASTROGRAPHY, and yjafw,] the science of describ-
ing the stars. '
ASTROITES, or STAR-STUiN E. See Asteria, and Plate Y.
ASTROLABE , [of «rgov, and to take.] 1. An instru-
ment chiefly used for taking the altitude of the pole, the sun, orstars, at sea —2. A stereographic projection of the circles of thesphere upon the plane of some great circle.
Astrolabe, is also an instrument formerly used for taking thealtitudes of the sun and stars at sea. It consists of a graduatedcircular part A BCD, (Plate V. fig. 6.) with a moveable indexFG, carrying two sights, which in using the instrument are to bedirected to the object, while the instrument is suspended by thering. T^his instrument has long been laid aside by navigators, itbeing insufficient, on accolint of the ship’s motion.
ASTROLOGER , [astrologus, Lat. from aroov and Xoy©-',]one that, supposing the influences of the stars to have a casualpower, professes to toretel or discover events depending on thoseinfluences. It was anciently used for one that understood or ex-plained the motions of the planets, without including prediction.
ASTROLOGY , [from a star, and xoyo,-, discourse,] waslong considered as a Science, by which future events could beforetold, from the aspects and positions of the heavenly bodies.In the literal sense of the term, astrology should signify no morethan the doctrine or science of the stars; which was its originalacceptation, and made 'the ancient astrology ; though, in the
course of time, an alteration has arisen; that which tiie ancientscalled Astrology,, being afterwards termed Astronomy . Astro-logy may be divided into two branches, natural and judicial.
Astrology, Judicial, or Judiciary , which we commonlycall simple astrology, is that which pretends toforetelmoral events;i. e. such as have a dependence on the free will and agency ofman ; as if they were directed by the stars. This art, which owedits origin to the practices of knavery on credulity, is now univer-sally exploded by the intelligent part of mankind.
Astrology, Natural, comprehends the predicting of natu-ral effects; as, the changes of weather, winds, storms, hurri-canes, thunder, floods, earthquakes, &c. This art properly be-longs to physiology, or natural philosophy ; and is only to be de-duced a posteriori, from phenomena and observations. For thisspecies of astrology, Mr. Boyle makes an apology, in his Historyof the Air.
AS PROMETER, [arg°v, and fwTjuu, to measure,] an astronomi-cal instrument, by means of which the rising of the sun, stars, and| planets, their positions, &c. may be ascertained. See a descriptionof it in the Phil. Trans. No. 70, or the Retrospect, No. 10.
AST ROM ETEORO LOG I A, [*rja», and xoy© 1 , Gr.]
the art of foretelling the weather, audits changes, lrom the aspectsand configurations of the moon and planets. This makes a spe-cies of astrology, distinguished by some under the denominationof Meteorological Astrology .
ASTRONlUM, in botany, a genus of the pentandria order,and dioecia class. Male calyx five-leaved; corolla quinquepeta-i lous: Of the female the calyx and corolla are the same as in the! maid; stvli three ; seed single. There is one species, a tree 6f! New Spain.
| ASTRONOMER, [from «rjov, a star, and vof*©-, a rule orj law,] one that studies th* celestial motions, and the rules byI which they are governed.
(1.) ASTRONOMY, [«r;o*o,w ‘«, from ar?°v, a star, anila law,] is a mixed mathematical science, teaching the knowledgeof the celestial bodies, their magnitudes, motions, distances, pe-riods, eclipses, order, &c. and the natural causes on which theirphenomena depend.
History of Astronomy.
(2.) Astronomy appears to be a science of the highest antiquity.From the account given by Moses', ol the creation of the lumi-naries, it is extremely probable, that our first progenitor receivedsome knowledge of their nature and uses from his Almighty Crea-tor himself. The Jewish Rabbins have adopted this opinion : andindeed, it is natural to think, that no visible objects would morereadily excite the curiosity, or appear more worthy of the con-templation of Adam in a state of innocence, than the celestialbodies. ✓
(3.) Accordingly Josephus ascribes to Seth and his posterity, aconsiderable degree of astronomical knowledge. lie speaks oftwo pillars, the one of stone, and the other of brick, called the-» pillars of Seth, upon which they engraved the principles of thescience ; and he savs that the former was still entire in his time:Josephus adds, that longevity was bestowed upon the Antedilu-vians, for the very purpose of cultivating the sciences of geome-try and astronomy; observing, that the latter could not be iearnedin less than 600 years; “-for'that period,” he observes, “is thegrand year.”
(4.)’ By this remarkable expression, is probably meant, theperiod inwhich the sun and moon come again into the same situ-ation in which they were at the beginning of it,, with regard to thenodes, apogee of "the moon, &c. “ This period,” says Cassini,
“ of which we find no intimation in any monument of any othernation, is the finest period that ever was invented; for it bringsout the solar year more exactly than that of Hipparchus and Pto-lemy ; and the lunar month within about one minute of what isdetermined by modern ahronomers.” If the Antediluvians had*uch a period of 600 years, they must have known the motions
of the sun and moon more exactly than their descendants knewthem, for many ages after the flood.
(5.) The origin of astronomy and astrology is fixed by mostauthors either in Chaldea or Egypt ; and accordingly among theancients we find the word Chaldean often used for astronomer, orastrologer. Indeed both these nations pretended to a very highantiquity, and claimed the honour of producing the first cultiva-tors of this science. The Chaldeans boasted of their temple ortower of Belus, and of Zoroaster , whom they placed 5000 yearsbefore the destruction of Troy ; while the Egy ptians boasted oftheir colleges of priests, where astronomy was taught, and of themonument of Osymandyas, in which it is said, there was a goldencircle of 365 cubits in circumference, gnd one cubit thick, di-vided into 365 equal parts, according to the days of the year, &c.It is indeed evident, that both Chaldea and Egypt were countriesvery proper for astronomical observations, on account of the ex-tended flatness of the country, and the purity and serenity of theair. The lower of Belus, or of Babel itself, was probably an as-tronomical observatory ; and the pyramids of Egypt , whateverthey were originally designed for, might perhaps answer the samepurpose; at least they shew the' skill of this people in practicalastronomy, as they are all placed with their four fronts exactlyfacing the cardinal points of the compass.
The Chaldeans began to make observations soon after the confu-sion of languages, as appears from the observations found there onthe taking of Babylon by Alexander; it is probable they beganmuch earlier. 'They determined, with tolerable exactness, tinslength both of a periodical and synodical month. They discovered,that the motion of the moon was not uniform ; and they even at-tempted to assign those parts of the orbit in which the motion isquicker or flower. W'e are assured by Ptolemy that they werenot unacquainted witRthe motion of the moon’s apogee and nodes,the latter of which they supposed made a complete revolution in6585]- days, or a little more than 18 years, and contained 223 com-plete lunations, which period is called the Chaldean Saros.