Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/120

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Dr. Shaw on this occafion obfefves* that if the medicinal virtues of nitre, were to be enumerated, as they ftand con- firmed by fufficient experience* perhaps they would prove more numerous than thofe of any one known medicine befides. It is ferviceable in the ftone and ftoppages of urine, in deli- rium?, malignant fevers, diarrhseas^ the fmall pox of the confluent kind, &c. fo as to prove almoft a general remedy. And all thefc excellent qualities are in this fait, joined to that defirable property of being innocent, or fcarce any way pre- judicial to the body.

Plummer's rethiops is another powerful Alterant. Sec Plum- MER's Mthiops.

ALTERATION" (Cycl) is ufed in medicine to denote a change in the ftate and qualities of an animal body, in refpect of temperature or conftitution, health or ficknefs. In this fenfe, Alteration includes both evacuation and accre- tion. Linden, Sol. Med. Ex. 13. §. 335. feq-

Alteration is more ftrictly taken for a change in the quality of the body, contradiftinguifhed from evacuation and apportion. In which fenfe, Alteration is the effect of medicines called Alterants. See thearticle Alterant. Alteration is one of the two great branches, or operations of phyfic, whereby chiefly the humours, when in a ftate of diforder, and threatening danger to the body, are prepared, changed or corrected in various manners, to the end that they may be more commodioufly and fafely evacuated af- terwards. J wick. Confp. Therap. Tab. 12. p. 348. Alteration is chiefly applied in refpect of the fluids, or hu- mours of the body. When applied to the foiids, it is chiefly in refpect of the humours, or the motions thereof. Alteration is fometimes alfo applied in refpect of the vital mo- tions of the body.

Thus fpecifics arc applied to alter and rectify convulfive and other diforderly motions. The Alteration of the humours is either extrinfic, or intrinfic.

Extrinjic Alteration isachange produced in the fenfiblc ap- pearances, as colour, thicknefs, and the like.

Intr'tnjic Alteration isachange in the primitive crafis, or conftitution of a fluid, funck. loc. cit.

Alteration, in a fenfe ft ill more ftrict, denotes that con- verfion which the food undergoes, to render it nourifhment. In this fenfe Alteration both includes the digeftion a performed in the ftomach, and the afnmilation in the habit of the body b. — F* Gal. de Sympt. Cauf. 1. 3. c. 2. l Id. de Compof. Med. I. 8. c. 6.]

It is difputed among phyficians what the Alteration is, which the food undergoes.— Some reduce it to a mere comminution or trituration. — Others afl'ert a total tranfubftantiation. Mem. de Trev. 1714. p. 2007. See Digestion, Cycl. and Suppl.

Alteration, in alchemy, denotes the converfion of one body into another by fimiHtude. V. Caji, Lex. Med. in vqc. Alter atio.

Cofmographers fpeak of Alterations on the face of the earth % Alterations in refpect of land and water* 1, Alterations on the face of countries. Astronomers f mention Alterations in the heavens, the ftars, &c. s. Naturalifts tell us of Alterations in the vifcera of the earth. Some have fuggefted Alterations of the meridian, of the earth's center h of gravity, the place of the poles in the heavens, the axis of rotation '• — [ c Wooclw. Nat. Hift. Earth, p. 36, and 248. d RowL Mon. Ant. p. 5. 8, cs'c. Hook, Pofth. Works, p. 312. ° Jour, des Scav. T. 68. p. 488. f Nicwent. Reiig. FhUof p. 435. Kcckcrm. Syft. Mathem. p. 201. g Kirch. Mund. Subterr. 1. 8. Sec. I. c. 5. p. 9. Hook, loc. cit. p. 346. h Hook, loc. cit. p. 345, 540. ! Id. ibid. p. 322, 345, 349, 353, 357, 359, 551.] Concerning the Alterations of bodies by chemical Ana- lys. See Mem. Acad. Scienc. An. 1718. p. 262. Hift. Ejufd. An. 1721.P. 428. by mixture, Mem. Ejufd. An. 1718. p. 262. Of colours of hair, feathers, cjfe. Bac. Nat. Hift. Cent. 1, n. 93. Opp. T. 3. p. 24. feq. Of the colours of Fluids, Eft". Acad. Ciment. p. 138. Obferv. Halenf. T. ir. p. 29. Jour, des Scav. T. 76. p. 6. Of Difeafes, Medul. Medic, p. 29. 56. feq.

Alteration of ^hcantities, among algebraifts, denote what we otherwife call variations, or permutations. 'Jones, Synopf. p 216.

ALTERATIVE, in medicine, the fame with Alterant. See Al- terant, Cycl. and Suppl.

ALTERCUM, in botany, a name by which fome of the old authors exprefs the Hyofcyamus, or henbane. See Hyoscy- AMUS. Ger. Emac. Ind. 2.

ALTERITY is ufed by fome philofophers for diverfity. Stanl. Hift. Phibf. p. 828. See Diversity, Cycl. The word is formed of the Latin Alter, another. Alterity amounts to the fame with what others call Aliety, Alietas, Scherz. Man. p.' 14. ALTERNATE, or ALTERNATIVE (Cycl.)— Alterna- tive Proviife, is where two or more are engaged to do a thing under a disjunction, fo that both are under obligation, though if either of them difcharge it, both are acquitted. Calv. Lex. Jur. p. 62.

This is otherwife called a disjunctive promife. An Alternative, or disjunctive proportion is true, if one fide or part of it be true. 3

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ALTERNATION,' (Cycl) in Its primary fenfe, denotes a fuc- ceflion by turns. Fejt. de Verb. Signif- p. 10.

Alternation is more particularly ufed among civilians for disjunction, as in faying this or that. Mr iff", dc Verb. Signif. p. 41. Calv. lib. cit. p. 62.

ALTERNATIVE. See Alternate. -

ALTH/EA, Marjh-maU&w, in botany. See Marsh-mallow.

ALTINCAR, among mineralifts, a fpecies of factitious fait ufed in the fuuon and purification of metals. Gafl. in vac. The Altincar is a fort of flux powder. Divers ways of pre- paring it are given by Libavius. Synt. Arcan. Chym. 1. 8. c. 38!

ALTITHj in botany, a name given by fome authors to the plant of which the AJfafatida of the Ihops is the gum. Bont. p. 41.

ALTITUDE (Cycl.)— Determinative Altitude, Altitude Determinatrlx, is ufed by feme write! s for the height from whence a falling body by its natural acceleration acquired a certain velocity^ H:ra>an, Phoron. i. 1. p. 92.

Circles of Altitude are ul'ually known by the name of Al- mucantars. See Almucamtar, Cycl. Some have fufpected a variation in the apparent folftitial Al- titudes of the fun.' Something of this kind was perceived by M. Cafliniiii 1655. by means of the great gnomon hi .the church of St. Petronius at Bologna ; which wag father-- confirmed by other observations at the royal obfervatory at Paris. The variation obferved by M. Cailini during the courfe of twenty two years, only amounted to a few fecpnds. And by com- paring the obfervation made by Phytheas at MaiiUilles three hundred years before Chrift, with another made by Caftini in 1672 at the fame place, it appears that in two thoufand years time, this difference of Altitude has only amounted to a few minutes. V.Mem. Acad. Scienc. 1693. p. 180. feq, SeeEcLiPTic.

The Altitude of the fun, it is faid, may be found to a few feconds, with an inftrument of three foot radius. But this is rarely found in fact 3. A French engineer, M. Hautefeuille has propofed a new inftrument, whereby he pretends to take Altitudes even to thirds b. — [ a Jour, des Scav. T. 32. p. 33. feq. b Wlem de Trev. 1704. p. 440.] To find the fun's Altitude by the globe. See Globe, Cycl

Altitude of a Star, or other point, is properly an arch of a vertical circle, intercepted between the aifigned point and the horizon a. Or it is the arch of a circle, perpendicular to the horizon, in whofe center the fpeetator is, terminated by the horizon and the ftar b .— [ a Wolf. Elena* Aftron. §.86. ^Gravefende, Mathem, Elem. T. 2. n. J 105.] See Vertical, Cycl.

An irregularity has been obferved in the apparent Altitudes of the ftars near the Meridian. On fome occafions, when they are mounting towards the meridian, they appear to fall, and after patfing the meridian, to rife. Hift. Acad. Scienc, 1719. p. 75. feq. See Meridian, Cycl Mariners can rarely take Altitudes of the ftars to lefs than five, fix, or feven minutes. And as there is no fixed me- ridian aboard of a fhip, as at land, the continual motion of the vcfil-1, will be perpetually changing the -ftars Altitude; befides, that their inftruments are commonly coarfely made ; an error of fix minutes, will make an error of a tenth part of a degree, viz, two leagues or upwards, in taking a latitude. Hift. Acad. Scienc. 1722. p. 145. See Latitude, Cycl. The difference of Altitude of a ftar, according as the obferver is ifuppofed in the center, or on the furface of the earth, makes what we call the parallax of the ftars. Gravefend. lib. cit. n. 1 106. See Parallax, Cycl. M. Parent has given a new method of taking Alt'ttudts at fea, with a common watch. As the celeftial tables give us the right afcenfions, and declinations of all the fixed ftars, we have only to obferve the difference of time between the rifing of two ftars, and in this difference fcparating that which arifes from their different pofition from that which arifes from the obliquity of the fphtre, which laft will be the Altitude of the pole of the place of obfervation.

As we cannot have too many ways of finding the poles Alti- tude at fea, this method may be fure, fince- here no other obfervation is required, but that of the rifings of two ftars, the difference of time between thefe is fufticiently given by a watch, without being any of the beft, fince it can hardly erE much in the three or four hours between the rifings of -the two ftars. One difficulty feems to occur, viz. that the fhip is not fixed, but will have changed its place between the two obfervatidns. To which it is anfwered, that the little 'way a fhip has made, either in longitude or latitude, between two observations, which will ufually be. at no great diftance from each other, may be fafely neglected. At the worfty'if the. fhip has made any confiderable way, it need- only -be efti- mated in the ufual manner of reckoning. Vid. Hift; Acad. Scienc. an. 1703. p. 107. feq.

The Altitude of the equator above the horizon is fometimes alfo called its elevation. Mem. Acad. Scienc. 1714. p. 87. WolfiYXzux. Aftron. p. 397. feq. See Elevation, Cycl.

Altitude of the tropics amounts to the fame* with What is otherwife called the foljlitial Altitude of the fun. • Mem. Acad, Scienc, 1714. p. 89. - - : - - ■

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