Page:Cyclopaedia, Chambers - Volume 1.djvu/570

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DIA

Dialling -.?/&!-?, is anlnftrument made ofBrafs, witn fevcral Semi-Circles Aiding over one another, on a moving. Hciron, to demonftrate the Nature of the Doarine ofSphe- rical Triangles, and to give the true Idea of drawing Dials on all manner of Planes. ,

Dialling-Z/'otj, ovScalcs, are graduated Lines, placed on Rules, or the Edges of'Quadrants, and other Inftruments, toexp.-dite the Conftruflion of Dials. See Scale.

The principal of thefeLincs are, 1. A Scale of fix Hours, which is only a double Tangent, or two Lines of Tangents each of 45 Degrees, joyn'd together in the Middle, and equal to the whole Line ofSines, with the Declination fet againft the Meridian Altitudes in the Latitude of London, fuppofe, or whatever Place it is made for. The Radius of whicnLine of Sines is equal to the Dialling-Soak of fix Hours. 2. A Line of Latitudes, which is fitted to the Hour-Scale, and is made by this Canon; As Rad. to the Chord of 90 De- frees : So are the Tangents of each refpe&ive Degree of the Line of Latitudes to the Tangents of other Arcs. And then the natural Sines of thofe Arcs are the Numbers, which taken from a Diagonal Scale of equal Parts, mall gra- duate the Divilions of the Line of Latitudes to any Radius. The Line of Hours, and Latitudes is general for pricking down all Dials with Centres.

Dialling, in a Mine, call'd alfo "Plumming, is theufing of a Compafs, (which they call Dial) and a long Line, to know which Way the Load, or Vein of Oar inclines, or where to fhift an Air-Shaft, or bring an Adit to a defir'd Place. See Mine.

The Manner thereof, See under the Article Ti N.

DIALIA, in Antiquity, Sacrifices perform'd by the Fla- tten Dialis. SeeDiALis.

'Twas not, however, of fuch abfolute Neceflity, that the Dialia were perform'd by the Flamen Dialis ; but that others might officiate. We find in Tacitus Annul. Lib. III. Cap. ;8. that if he were fick, or detain'd by any other pub- lic Employ, the Pontifices took his Place.

DIALIS, in Antiquity, a Latin Term, fignifying fome- ivhat that belongs to Jupiter, to Zzvt A/o<.

The Flamen Dialis, then, was a Pried: of Jupiter. He was never permitted to fwear. See Flamen.

DIALOGUE, a Convcrfation of two or more Perfons, cither by Word of Mouth, or in Writing.

The Word is form'd from the Latin Dialogus, of the Greek A/aAoj-of, which fignifies the fame Thing.

Dialogue, is the mod ancient Form of Writing. See Dialectic.

The firft Authors wrote moft of their Trcatifcs therein. ThcArch-Bilhop of Cambray gives an admirable Painting of the Advantages of Dialogue, at the Head of his Paftoral Inflruction. See the Word Dramatic.

The Holy Spirit bimfelf has not difdain'd to teach us in Dialogue, viz. Patience, in the Book of Job, and Love of God, in the Canticles. Jufiin Martyr open'd this Way, in his Controverfy againft the Jews; and Mintitius Felix fol- low'd it in his againft the Idolaters. 'Tis in this Form, that Origen jug'd he could beft refute the Error of Marcion. The great Jtbanafius thought it no Diminution to the Maiefty of Myfteries of Faith, to maintain tmm by the Fa- miliarity of Dialogue. This Way of Writing St. Safil thofe as the moft proper to convey thofe Rules, which have fmce illumined all the Eaft. The Arts of Dialogue were admirably put in Praffice by Gregory Nazianzeu, and his Brother Gejarius, for conveying the fublimcft Truths. Sulpi- tius Severus could not do better, than publifli the Wonders of Solitude in a Kind of Conventions. A Volume ot'St. Cy- ril of Alexandria, is almoft fill'd with Dialogues, where- in he explains the moft Dogmatical Truths, relating to the Incarnation. The Myftery of Jefus Cbrijl is treated of in the fame manner, by the Learned Tbeodoret. St. Chryfofiom found no Method more promifing to exprefs the Eminence, and Danger of the Priefthood. Who is not acquainted with the beautiful Dialogue of St. Jerom, wherein he refutes the Luciferians ? "Who does not admire St. Augtlfiine's Dialogues, and efpecially thofe on free Will, where he goes back to the Origin of Sin ; againft the Manicbees > The Tradition of the Solitaries in the Defert, is finely illuftra- ted in the Conferences of Caf/ian, which have fpread the fame Light through the Weft, that the Eaft receiv'd from St. Safil. Gregory theGreat deem'd Dialogue worthy the Gravity of the Apoftolic See. The Dialogues of St. Maxi- mus, on the Subject of the Trinity, are famous through- out all the Church. St. Anfelm fhew'd the Force of his Genius in his Dialogues on the Fundamentals of Religion. Profane Antiquity likewife made Ufc of the Art of Dia- logue, and that, not only on humourous, and comical Sub- jects, as Lucian did, but alfo on the moft ferious, and ab- ftracl: ; Such are the Dialogues of Tin to, and thofe of Ci- cero, which turn altogether on Subjects of Philofophy, or Politick. Among the Moderns, the principal Dialogifis, are Monfr. de Feuelon, Arch-Bilhop of Cambray ; Mr.'Pajcbal,

in his 'Provincial Letters ; F. Soubours, in his Entretiens d'Arifie, & Eugene 5 Monfr. Fomenelk, in his Dialogues on the Dead, and Plurality of Words, l$c.

Dialogue, in Mufic, is aCompolition for at leaft two Voices, or two Inftruments, which anfwer each other 5 and which frequently uniting make a c frio with the Thoro'- Bafs. y fa

There are Abundance of Dialogues in the Italian Opera's.

DIALTHjEA, in Pharmacy, an Unguent thus call'd from its Softs, which is the Root of the Altbtea.

It confifts of Mucilages drawn from that Root, and from the Seeds of Line, Squills, andFennigreek. The other Ingre- dients are common Oil, yellow Wax, Refin, Turpentine, Galbanum, and Ivy-Gum.

It is efteem'd proper to foftcn, and refolve; affwageS Pains of the Side, foftens Callus's, and ftrengfhens the Nerves. 'Tis applied, by rubbing it on the Parts af- fefted.

DIALYSIS, in Grammar, a Character confifting of two Points .. placed over two Vowels of a Word, which would otherwife make a Diphthong ; but are here parted into two Syllables. See Vowel, and Diphthong. ,

DIAMARGARITON, in Pharmacy, a Medicine deno- minated from Pearls, call'd in Latin Margarita ; which are a principal Ingredient therein. See Pearl.

There are two Kinds : The Hot, and the Cold.

The HotDiamargariton, is a Powder compofed of Pearls, Pellitory, Ginger, Nutmeg, Cinnamon, and divers other hot Ingredients. It is reputed Hyftcric, ftrengthens the Womb, promotes the Menfes, and affifts in Digeftion.

ColdDiamargariton, is a folid Electuary, compofed of Pearls ground-fine, and white Sugar diifolved in Rofc- Water, or Buglos, and boil'd to a Confidence. It ftrengthens the Stomach, moderates the too abundant Acids, flops the fpitting of Blood, and Loofenefs of the Belly.

Compound Cold Diamargariton, is a Powder made of Pearls, red Rofes, Flowers of Nenuphar, and Violet, Lig- num Aloes, red and Citron Santal, Tormentle Root, Seeds of Melon, Endive, &c. It is applied to give Vigour, faci- litate Refpiration, and reftfi the Malignity ot Humours.

DIAMASTIGOSIS, in Antiquity. It was a Cuftom among the Lacedemonians, for the Children of the moft diftinguifh'd Families, to ilalh and tear each others Bodies with Rods before the Altars of the Gods: The Fathers, and Mothers, who were prei'ent at the Spectacle, animating and exciting them all the while, not to give the leaft Sign of Pain, or Concern.

This they a\V&Diamafiigofis, a Greek Term, derived from JVKj/cusjyoilV, to whip, cudgel.

TheDefign hereof, apparently, was no other than to harden their Youth, and enure them betimes to Blows, Wounds, i$c* that they might defpife them when they came to War.

DIAMETER, in Geometry, a right Line pafling thro' the Centre of a Circle, and terminating on each Side by the Circumference thereof. See Circle.

Or, the Diameter may be defined a Chord pairing thro' the Centre of a Circle : Such is the Line A E {Tab. Geo- metry F/g. ~7 .) palling through the Centre C. SeeCHORn.

Half a Diameter, as CD, drawn from the Centre C td the Circumference, is call'd the Semi-Diameter, on Radius. See Radius, iSc.

The 'Properties of the Diameter.

1. The Diameter divides the Circumference into equal Parts. And hence we have a Merhod of Defcribing aSemi- Circle upon any Line ; affuming a Point therein for the Centre. See Semicircle.

a. The Diameter is the greateft of all the Chords.

3. To find the Ratio of the Diameter to the Circum- ference.

This Ratio has been greatly fought for by the Mathema- ticians : And no wonder : in as much as if this were juftly given, rhe Quadrature of the Circle where atchiev'd. Sec Quadrature.

Archimedes firft propofed a Method of finding it by Regular Polygons, inferib'd in a Circle ; till arri- ving at a Side fubtending an exceeding fmall Arch, and then feeking the Side of a Similar Polygon cir- cumfcrib'd : Each of the'e being multiplied by the Num- ber of Sides of the Polygon, gave ; the Perimeter of the Poly- gon both inferib'd, and circumfcrib'd. In which Cafe theRa- t, of the Diameter to the Circumference of the Circle was greater than that of the fame Diameter to the Perime- ter of the circumfcrib'd Polygon, but left than that of the Diameter to the Perimeter of the Polygon inferib'd. The Difference between both gives the Ratio of the Dia- meter to the Circumference in Numbers nearly true.

That Divine Author, as already obferved, by Polygons of 95 Sides found the Ratio of the Diameter to the Circum- ference to be as 7 to «. via. Suppofing the Diameter 1,