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The Afibma is ufually divided into Moifi and Dry, or Manifeft and Ogult, or Pneumonic and Convulfive: The firft attended with an Expectoration of purulent Matter; the latter without.
The true Afibma is occafioned by an abundance of Serofities, or of grofs vifcous or purulent Humours, collected in the Ca- vities of the Lungs, which flop up or ftraighten the Paflages of the Air, and comprefs the Bronchia. See Bronchia.
It is alfo owing to Empyema's, Phtbifis's, Crudities in the Stomach, Cachexies, &c. See Empyema, Phthisis, &c. ( The convulfive Afihma is fuppofed to be occafioned by an ir- regular Motion of the Animal Spirits; and happens when the Spirits' do not flow faft enough, or in fufficient Quantity, into the Mufcles of the Breaft, either by reafon of an Obstruction, or of fome other Obftacle: The neceffary Confequence where- of is a violent and painful Refpiration. — The Afihma, again, is either continual, or periodical, and intermitting; which kit returns chiefly where a fober Regimen is not obferved.
The Aftbma is found to be the moft violent when the Patient is in Bed, and in a prone Poiture ,■ the Contents of the lower Belly, in that cafe, bearing againft the Diaphragm, fo as to lelTen the Capacity of the Breaft, and to leave the Lungs lefs room to move.
The Cure of the true or pneumonic Afibma, is by bleeding; after which Emeticks may be ufed ; and if the Paroxyfm returns, Epifpafticks, with Glyfters inftead of Purges. — Infulions of Fim. Equin. or the Juice thereof, being deteriive and attenuating, are reputed excellent Lin&ufs alfo contribute to the Cure, Mille- pedes, Spirit of Gum Armani ac, with Sal Armo?iiac, Coffee, Tin- cture of Sulphur, &c. are commended in Afihmatick Cafes.
For the convulfive Kind, the Cure is attempted by Antiepi- leptkks, Antihyflericks, Antifpafmodicks, Opiats, &c.
ASTRAGAL, Astragalus, in Anatomy, a Bone of the Heel, having a convex Head, articulated with the two Focils of the Leg, by Gmglymus. See Heel and Foot.
The Afiragalus call'd Talus, and Os Balifia, is the firft Bone of the Tarfus. See Talus and Tarsus.
Some alfo apply the Name to the Vertebra of the Neck. — Homer, in his Odyjfee, ufes the Term on this Occalion. See Ver- tebra.
Astragal, in Architecture, is a little round Member, in form of a Ring, or Bracelet j ferving as an Ornament on the Tops and at the Bottoms of Columns. See Moulding, Co- lumn, &c.
The Afiragal is fometimes alfo ufed to feparate the Fajciai of the Architrave ; in which cafe it is wrought in Chaplets, or Beads and Berries,
It is alfo ufed both above and below the Lifts, adjoining im- mediately to the Square, or Die of the Pedeltal. See Dye and Pedestal.
The Word is derived from the Greek #?$*.*/«■*&, which figni- fies the Ankle or Ankle-Bone.
Astragal, in Gunnery, is a Kind of Ring or Moulding on a piece of Ordnance, at about half a Foot's Diftance from the Mouth ; ferving as an Ornament to the Piece, as the former does to a Column. See Ordnance, Canon, see.
ASTRAL, fome thing belonging to the Stars, or depending of the Stars. See Star.
The Word comes from the Latin afirum, of the Greek «V^, Star. 1
Astral, or SiderialTear. See Siderial and Year.
ASTRINGENTS, Astringentia, in Medicine, binding Remedies ; or fuch as have the Power of contracting the Parts, and diminiihing the Pores thereof. See Medicine.
Afiringents act either by the Afperity of their Particles, where- by they corrugate the Membranes, and make them draw up clofer ,• or by thickening the Fluids, whereby they cannot run off fo faft as before.
Afiringents therefore fland oppofed to Laxatives. See Lax- ative, Purgative, &c.
Hence, Afiringents are of the Clafs of Strengtheners, or Cor- roborants ; the Nature and Operation whereof, fee under the Ar- ticle Strengthened.
Afiringents only differ from Stypticks, in Degree of Efficacy. See Styptick.
The Word is compounded of the Lathi ad and ftringo, I bind.
Among Simples, Mint, red Rofes, Nettles, Sanicle, Barba- ries, Quinces, Pomegranates, Sloes, Cinnamon, Blood-ftone, Alum, Chalk, Boles, Coral, Tutty, <&c. are principal Afirin- gents.
ASTROITES, or Lapis Astroites, in Natural Hiftory, a Kind of figured Stone, found in divers Parts, and particularly the North of England See Figured-S/wzc
The Form thereof is very uniform and regular ; confiding of feveral thin pentagonal Joints let one over another, ib as to form a Kind of five-angled Column.— The ufual Figures, as given by Dr. Lifter, are reprefented in Tab. Nat. Hifiory, Fig. 14,.
Thefe Stones, as now found, are all Fragments, confifting of from 1 to 25 Joints.— The Matter or Subftance thereof when broken, is Flint-like, of a dark mining Politure, but much fofter, and eafily corroded by an scid Menftruum. — They creep, like che Comu Ammms-, in Vinegar; but a Granger Spirit, as of
Nitre, agitates them with fome Violence. See Cornu Am- moms.
The protuberant Parts reprefented under the top Joint of the firffc Figure are not found in all ■ but only in thole which are deep-jointed. — They are always five in Number. Dr. Lifter calls them Wyers $ and compares them to the Antennas of Lobfters.
'Tis controverted among the Naturalifts, to what Species of Bodies the Afiroitcs, Trocbites, Entrocbi, &c. are to be referr'd. Some will have 'cm Native Stones, others Rock-Plants, and o- thers Petrifactions of Plants. See Stone. See alio Petri- faction, Spar, Trochites, Entrgchi, <&c.
ASTROLABE, Astrolaeium, was originally ufed for aSy- ftem or AiTemblage of the feveral Circles of the Sphere, in their proper Order and Situation with refpect to each other. See Circle and Sphere.
The antient Afirolabes were the fame with our Armillary Spheres. See Armillary.
The firft and moft celebrated of this Kind was that of llippar- chus, which he made at Alexandria? the Capital of Egypt, and lodg'd in a fecure Place,- where it ierv'd for divers Aitrono- mical Operations. — Ptolomy made the fame ufe of it ; but as the Inftrument had feveral Inconveniences, he bethought himfelf to change its Figure, chough perfectly natural and agreeable to the Doctrine of the Sphere ; and to reduce the whole Afirolabe up- on a Plane Surface, to which he gave the Denomination of Pla- nifphere. See Planisphere.— Hence,
Astrolabe, is ufed among the Moderns for a Planifphsre; or a Stereograpbick Projection of the Sphere upon the Plane of fome Circle thereof. See Projection and Stereographick.
The ufual Planes of Projection are that of the Equinoctial, the Eye being fuppofed in the Pole of the World ; and that of the Plane of the Meridian, the Eye being fuppoied in the Point of Interferon of the Equinoctial ana Horizon.
Stojfler, Gemma Friftus, and Cavius, have treated at large of the Afirolabe. — for a further Account of the Nuttere and Kinds here- of, fie the Article Planisphere.
ASTROLABLE,or&^ Astrolabe, is an Inftrument chiefly ufed for taking the Altitude of the Pole, the Sun, or Scars, at Sea. See Altitude.
The Afirolabe reprefented Tab. Navigation, Fig. 22. confifts of a large Brafs Ring, about 15 Inches in Diameter, whole Limb, or a convenient Part thereof, is divided into Degrees and Mi- nutes ; fitted with a moveable Index, or Label, which turns up- on the Centre and carries two Sights.— At the Zenim is a Ring, to hang it by in time of Obfervation.
To uie the Afirolabe, turn it fo to the Sun, as that the Rays may pafs freely through both the Sights FandG,- in which Cafe, the Edge of the Label cuts the Altitude in the divided Limb.
The Afirolabe, though now grown into difufe, is at leait equal to any of the other Instruments ufed for taking the Altitude at hei; especially between the Tropicks, when the bun comes near the Zenith.— There are a great many other ufes of the Afirolabe^ whereof Clavius, Henrion, &c. have wrote entire Volumes.
The Word is form'd from the Greek drug, Star, and ;i*/a/3*»»., Capio, I take— The Arabs call it, in their i'ongue, Afiharlab; a Word form'd by Corruption from the common Gre^Naine: Though fome of 'em have endcavour'd to give it an Arabick Ori- ginal. But the learned arc generally fatisfied that \he Arabs bor- rowed both the Name and the Ule or the instrument from the Greeks.- — NaJJt Rcddi Thoufi has a Treatiie in the Pcrfian Lan- guage, enti led, Bait Babfil Afiarlab, \\ herein he teaches the Struc- ture and Abdication of the ^Jfirohbc.
ASTROLOGY, Asttolo&ia, the Art of foretelling future Events, from the Afpects, Portions, and Influences of the Hea- venly Bodies. See Aspect, Influence, &c.
The Word is compounded of the Greek <z??.e, Star, and Aayo?, Difcourfe; whence, in the literal Senit of the Name, Afirology ihould fignify no more than the Docir'mc or Science of the Stars i which we read was its original Acceptation, and made the anti- ent Afirology ; though, in Courfe of Time, an Alteration has a- rofe,* that which the Antients called Afirology being by us term- ed Aftronomy. See Astronomy.
Afirology may be divided into two Branches, Natural and Ju- diciary.
To the former belong the prediaiug of natural Effects; as, the Changes of Weather, Winds, Storms, Hurricanes, Thunder, Floods, Earthquakes, &c. See Natural. See alfo Weather, Wind, Rain, Hurricane, Thunder, Earthquake, <&c.
To this our Countryman -Goad chiefly keeps, in his two Vo- lumes of Afirology ; wherein he pretends, that Inundations may be foretold, and an Infinity of Phenomena explained from the Contemplation of the Stars.— Accordingly, he endeavours to ac- count for the Diverfity of Seafons, from the different Situations and Habitudes of the Planets, from their Retrograde Motior.s; the Number of flx'd Stars in the Constellations, ere.
This Art properly belongs to Phyfiology, or Natural Philo- sophy.
Its Foundation and Merits the Reader may gather from what we have faid under the Articles, Air, Atmosphere, Weather, .^Lther, Fire, Light, Comet, Planet, Magnetism, EffluvjAj &c.
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