DIA
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DtA
>fliis Dial being duly plac'd after the maimer of v ^ a . rs ,ha\Dial, and the 12 a-CIocic Line brought to the Sv of the Moon's Age ; The Shadow of the Index will „ive the hour.
° =fo uje a Solar, as a Eunar-Dial, i.e. to find the
Hour of the Night by a Sun-Dial.
Ob r erve the Hour, which the Shadow of the Index points
j,. Moon-Light : rind the Moon's Age in the Calendar,
d multiply the Number of Day by jf, theProdufl is the
y umber °i Hours to be added to the Hour lhewn by the
si adoWi ,0 B ive t ' ie Hour re 1 uire <l-
-pp,lECT; the peculiar Language of fome Province, cr p art of a !N ation, form'd by Corruption of the general, or Jnonal Language. See Language.
Uomer could fpealc 5 different Languages in one Verfe, - f , five DiateSs, viz. the Attic, ffomc, Molic, Hone, '" & the common Language of the Greeks. See Greek, Attic, Jonic, SSc. The lioloimefe, Sergamas, To/can, &c. are thcDialeBs c fa Italian. See Italian.
The Gafcon, undpiccard, are the Dialects of the French. c K French, SSa
DIALECTIC A, the Art of Logic; or, of Thinking, and Rcafoning juftly. See Log 1 c.
Zeno Ideates was the firfl who difcover'd the natural Scries of Principles, and Conclufions, obferved in Reafbn- jug and form'd an Art thereof, in Form of Diaiogue, which for this reafon was call'd DialeBica.
The Word comes from the Greek JVaA£jcT/KM, of the very jlittMyiti**} difjerere, to difcourfe, reafon.
The DialeBica of the Ancients isufually divided into fe- vers! Kinds : The firft was the Eleatica, that of Zeno Elea- Je s • which was threefold : viz. Confecutionnm, Colloquu- timwr., and Conteutiarum. The firfl confiding of Rules for deducing, or drawing Conclufions : The fecond, the Art of Dialogue, which became of fuch univerfal Ufe in Philofojhy, that all Rcafoning was call'd Interrogation. Then, Syllogifm being laid a-fide, the Philofophers did all by Dialogue ; it lying on the Refpondent, to conclude, and ar<uie from the feveral Conctflions made. See Dia- logue.
The laft PartofZCTM's Dialetlicks, ep/siita, was Conten- tious, or the Art of Difputing, and Contradicting ; tho' fome, particularly Laertms, afcribe this Part to 'Protago- ras, a Difciplc of Zeno.
The fecond is theDialetlica Megarica, whofe Author is Undid, not the Mathematician, but another* of Megara. He gave much into the Method of Zeno, and 'Protagoras : Tho' there arc- two Things appropriated to him : The firfl, that he impugned the Demonllrations of others, not by Af- ftmptions, bur Conclufions ; continually making Illations, and throwing in Ergo, Ergo, Ergo. The fecond, that he fet a-fide aR'Arguments drawn from Comparifon, or Simi- litude, as invalid.
He was fucceeded by Eubv.lides, from whom the So- phiflic Way of Reafoning is faid to be deriv'd. In his Time the Art is defcribed as manifold ; Mentions, Fal- lens, EleSra, Obvelata, Acervalis, Cornuta, and Cal-oa. See Sophism.
The third is the DialcHica of Plato, which he propofes as a Kind of Analyfis, to direct the human Mind, by divi- ding, defining, and bringing Things ro the firfl Truth ; where beir." arrived, and flopping there a little, it applies it fclf to explain fenfible Things ; but with a View to re- turn ro the firfl Truth, where alone it can reft. Such is the Idea of Plato's Analyfis. See Analysis, Platonism; Academic, E?c. _^
The fourth is Ariftot le't Dialefiicaj containing the Doc- trine of fimple Words, deliver'd in his Book of Predica- ments : The Doctrine of Propofitions, in his Book, de In- terfretatione : That of the feveral Kinds of Syllogifms, in his Books of Analy ticks, Topicks, and Elenchus's. See Syllogism, Topic, Elenchus, Proposition, iSc.
The fifth is the Dialetlica of the Stoicks, which they call a Part of Philofophy, and divide into Rhetoric, and 2)ialeSic : to which fome add One, or Definitive, whereby Things are juflly defin'd ; comprehending likewife the Ca- nons, orCriterions of Truth. See Criterion, iSc.
The Stoicks, ere they come to treat of Syllogifms, have two principal Places, the one about the Word sig- nifying ; the other abour the Thing fignified. On Oc- cafion" of the firft, they confider Abundance of Things belonging ro the Grammarians Province, what, and how many Letters, what is a Word, Diction, Speech, &C- On Occafion of the latter, they confider Things themfelves, not as without the Mind, but as in it, receiv'd in by means oftheSenfes. Accordingly, they firfl teach, that, Nil fit in Intelletln, av.od ncn prms fitent in Senjzi, Whatever is in the Mind, paffes thither by theSenfes; and that, Aut In- cmfione fm, as Plato, who meets the Sight 5 Aut Simt(i- indme, as Cffar by his Effigy 3 Aut Proprtime, cither by
Enlarging, as a Giant or by Diminifhing, as a Pinmy Tranflatione, as a Cyclops ; Am Compofitime
H.M
Enlarging, as a Giant, or byD
'Eranflatione, as a Cyclops ;
Centaur; Aut Contrano, as Death- Am 'Privation* a<
blind Man. See Stoicks.
The fixth is Epicurus'* Diatetitc. For tnb s he feems to have defpifed Dialectic, he cultivated it with Vigour- He was only averfe to_ that of the Stoicks, who, he thought at- tributed too much thereto - 7 as pronouncing him alone wife, who was well verfed in "Dialetlicks. For this Reafon Epicurus Teeming to fet a-fide the common Dialetlicks had recourfe to another Way, viz. to certain Canons, which he fubftituted in their, ftead, the Collection whereof he call'd Canonica. And as all Queftions in Philofophy are either de Re, or de Voce 5 he gave feparate Rules for each. See Canonica.
DIALECTICAL Arguments, in Logick, are fuch as are barely probable, and do not convince, or determine the Mind to either Side of the Qucitiun. See Probability.
DIALLING, the Art of drawing Sun, Moon, and Star- 9)ials on any given Plane, or theSurface of any given Eodvi See Dial. * J
The Greeks and Latins call it Gnomonica, and Sciate- rica, by reafon it diftinguifhes the Hours by the Shadow of a Gnomon. Some call it 'Thoto-faaterica, by reafon the Hours are fometimes (hewn hy the Light of the Sun. LaiV ly, others call it Horologiography. See Gnomonica,
SciATERICA, £?Ci
The Antiquity of Dials is beyond doubt. Some attribute their Invention to Aiiaxejnems Milefim ; and others to Thales. Vitruvius mentions one made by the ancient Chtddee Hiltorian Serojhs. on a Reclining Plane; almoft parallel to the Equinoctial, call'd Hcmkychis- Ari- fiarthus Sam'ius invented the Hcmifphere Dial" And there were fome Spherical ones, with a Needle for ,a Gnomon. The tDifciis of Arifiarchtts was an Horizontal Dial, with. its Limb raifed up all a-round, to prevent the Shadows ftretching too far.
But it was late 'ere t\io.Ro?nans became acquainted witH Dials. The firfl Sun-i)ial atRome was fet up by ^Vapyrim Curjb, about the Year of the City 447, before which Time; fays 'Pliny, there is no mention of any Account of Time but by the Sun'sRifing, and Setting : It was fet. up in the Tem- ple of £>?/iri?2US, but went ill: About 30 Tears after, ML Valerius Mejfa la being Conful, brought out of} Sicily an- other Dial, which he let up on a Pillar near the Rojl'fum 3 but for Want of its being made for that Latitude, it could not go true. They made ufe of it ir Years 5 till Martins 'Philippus fet up another more exact.
But there fcem to have been Dials among tlie Jews much earlier than any of thefe. Witnefs the "Dial of Afoa&; who liv'd 400 Years before Alexander, and within 12. Years of the Building of Rome ; mentioned by Jfaiah Chap; XXXVIII. Verfe 8.
Dialling is wholly founded on the firfl Motion of the heavenly Bodies, and chiefly the Sun ; or rather on the Di- urnal Rotation of the Earth; So that theElemems ofSphe- ricks, and the Spherical Afkonomy mould be mailer'd, 'ere a Perfon advances to the Doctrine of Dialling. The Doc- trine, or Theory, we fay, for as to the Practice, or the Ope- rations themfelves, diftinet from the Demonftrations, nothing is moreeafy, and obvious.
The firft profefs'd Writer on Dialling, is Clavius ; whoi demonftrates all, both the Theory, and the Operations, after the rigid Manner or the ancient Mathematicians $ But Co intricately, that no body, we dare fay, ever read them all. Dechales, and Ozanam, give much eafier in their Courfesi and Wolfius in his Elements. Mr. 'Picard has given a new Method of making large Dials, by calculating the Hour r Lines ; And Mr. de la Hire, in his Dialling, printed in KJ83. a Geometrical Method of drawing Hour-Lines from certain Points determin'd by Obfervationi Eberhardiis Welperus, init5"2j. publifh'd \ii$ Dialling, wherein he lays' down a Method of drawing the Primary Dials on a veryeafy Foundation. The fame Foundation is defcrib'd at length by Sebafiian Munfier^ in his Rudimenta Matfcematiba, publifu'd in 1551. Sturmius, in 167 z. publifh'd a new Edition of Welperus' 1 * Dialling, with the Addition of a whole fecond Part, about Inclining, and Declining Dials, &c* In 1708. the fame Work, With Sturmms 1 * Additions, was re- publifh'd with the Addition of a fourth Part, containing 5°/- card's, and de la Hire's Methods of drawing large Dials, which makes much the beft, and fulleft Book on the Sub'- jea. Veterfon, Michael, andMu.ler, have each wrote on Dialling, in the German Tongue ; Coetfius, in his Iforfc logicgraphia plana, printed in 16S9. Gauppcnws> in" his Gnomonica Mechanic^ txA'Bion, in his Ufe of Mathema- tical Inftru?nents. . . r ^ n
DiALLiNG-G/^f, is ahlnftrument made of Brafsy or Wood, with a Plane fitted to the Horizon and an Index 5 particularly contrived to drzW all Sorts Ot Dials, and togue a clear Exhibition of rffe Principles Oi that Art.
