Page:Cyclopaedia, Chambers - Volume 1.djvu/594

 DIS

f 228 ]

DIS

DISTANCE, is properly the ihorteft Line between two Points, Objeds, egfft

The Word is alfo us'd figuratively for an Interval, not only in refpecl of Place, but alfo of Time, and Quality.

Thus, we fay the 2)ifia?2ce of the Creation of the World from the Nativity of fefits Ghrifi is upwards of 4000 Years : The 2)iftance between the Creator and Creature, is in- finite.

For the Vifion (^/"Distance, or the manner wherein we come by the Idea of 2)ifiance in Objefb. See Vision.

Distances, in Geometry, are meafur'd by the Cham, tDecempeda, &c. See Chain, ££c.

Inaccejfible Distances are found by taking Bearings thereto from the two Extremes of a Line whofe Length is given. See Plain Table, Theodolite, &c.

Distance, in Geography, is the Arch of a great Circle interfered between two Places.

To find the Hi fiance of two Places' A and B, (Tab. Geography Fig. 4.) far remote from each other: Aflame two Stations C and D, from which both the Places A and B may be feen, and with a proper Inftrument find the Angles ADC CDB ACD and DCB, and meafure the 2)ifiance CD.

Then in the Triangle ACD we have two Angles given ACD and ADC, together with a Side, from which, by an cafy Rule in Trigonometry, found under the Article Tri- angle, we find AD.

So alfo in the Triangle CBD the Bafe DC, and the Angles at the fame being given, DB is found.

Lafily, in the Triangle ADB, having the Sides AD and DB, together with the included Angle ADB, thetDifiance re- quired AB is found by the Rules given for the Refolution of Triangles. See Triangle.

The Height of a remote Object being known, to find its 2)ifiance, when the Eye firif defcries it ; And again, the Height of the Eye given, to find the fDifiance to which the Eve can reach on the Surface of the Sea, or Land : Add the Height of the Eye AB, {Fig. 5.) to the Semi- Diameter of the Earth BC, by which you have AC: And fince in the Rectangle Triangle ADC, the Sides AC and DC are given, the Angle DCA is found by the common Rule for Refolution of Triangles; the Quantity of which Angle forms the Arch DB ; which Arch converted into Feet, or the like, gives the 2)ifiavce required.

Suppofe, E. gr. the Height of the Eye AB ; which is fomewhst lefs than in a Alan of ordinary Stature. Since BC is 191595559, AC will be 19695544, and the Angle DAB will be found S9 57"Minutes, 45 Seconds. Confequently DCB, or the Arch DB is 2' 17" or 157" : And, therefore, iince 1° or 3600" make 345752 'Paris Feet, DB 150811- of a Foot. AJfer the fame manner we find the 1)ifiance AB, to which_ an Object of a given Altitude DB may be feen, and con- fequently we know what Distance we are off from an Ob- ject of a given Altitude, when we firft difcover the Top thereof.

Distance, in Navigation, is the Number of Degrees, or ^Leagues, fifa that .a Ship has fail'd from any Point. See Sailing.

Distance, in Aftronomy. The 2> i fiance of the Sun, Planets, and Comets, is found from their Parallax. See Parallax.

That of the fix'd Stars, as having no fenfible Parallax, we can little more guefs at. See Fixed Star.

The 2?i ''fiances of the Planets from the Sun and Earth, in Semi-diameter of the Earth, fuppofing the grearcfr. Ho- rizontal Parallax fi" ; and the Dimenfions of the Orbits, as affign'd by KeJ-ler, are as follow.

D/'/r.ficm

Great-

Mean.

Leaft.

Difi. from[Great- ] Mean

Leaft.

the Sun.

eft.

theEarth

eft. 1

Jupiter

34560

326925

308290

r)

380556

3»7S44

=7453=

Sarurn

187254

178640 170026

V-

222250

179259

136268

Mars

57=26

52326 47426

s

92221

5=944

13668

Eartb 34995

34377 3375-8

34996

34377

33759

Venus 55061

24SS9 1 24718

8

60056

34 54 s

9041

Mercury: 16142

13340I 10537

2

5H38

37179

23221

Mr. Caffini makes the Diftdaces fomewhat lefs ; as fup- pofing the Sun's Parallax a little greater.

Difi. from

Greac-

Mean.

Leaft.

Difi froni'Great-

Mean

Leaft.

theEarth.

eft.

che Earth

i eft.

Jupiter

24400c

2IOCCO

176000!

Venus

3S000' 22000

Saturn

143 000

l5;oOO

87000

Mercury

33000 22000 1 1000

Mars

59000

33500

800c

Moon

6s \ 57 53

Sun

22374

22D00

-.1626,

Dr. Hook, by exact Obfervations with a Telefcope of 16 Foot, perpendicularly placed, firlf. difcover'd, that the 'Difiances of the Stars from the Zenith is not the fame at

all Times of the Tear ; Particularly the bright Star in the Dragon's-hcad he found 17, or 30 Seconds nearer the Zenith olGreJhtim College, in the Brumal Solilice, than in the Efti- val. And after him Mr. Flamfteed ob&rvci the like Varia- tions in the Pole-Star.

Distance of the Sun from the Moons Node, or Apogee, is an Arch of the Ecliptic, intercepted between the Sun's true Place, and the Moon's Node, or Apogee. Sec Node.

Curtate Distance, is the 2)iftance of the Planets Place from the Sun, reduced to the Ecliptic. Sec Curtate.

Line ©/"Distance, in Perfpective, is a right Line drawn from the Eye to the principal Point : Such is the Line OF, (T'ab.'Perjpeffive Fig.io.) drawn between the Eye O, and the principal Point F.

This, as it is perpendicular to the Plane, or Tabic, can only be the Tliftance of the Eye from the Table.

Point o/*DiStance, in Perfpective, is a Point in the Ho- rizontal Line at fuch Dif.ance from the principal Point, as is that of the Eye from the fame. See Point.

Such is the Point P, or Q_, (Fab. PerfpeHive Fig. u.~) in the horizontal Line PQ_; whofe *Dijtance from the prin- cipal Point F, is equal to that of the Eye from the fame F.

Distance of the SaftionS, in Fortification, is the Side of the exterior Polygon. See Bastion.

DISTASTE, or DISGUST, a Lofs of Appetite, or an Averfion, or Repugnance to Foods which are commonly eaten. See Nausea.

1)iftdpe is held by Phyficians one of the principal Dif- orders oi the Stomach. It arifes from a Want of Senfation in the Upper Orifice of the Ventricle ; which may be occafioned various Ways : as, by a too great Abundance of Food ; thick, heavy Humors in the Stomach ; fat, viicid Aliment ■ Ob- ftructions of the Lacteals 5 Suppreflions of the ufual Eva- cuations 5 Intermifiior.s of the ordinary Excrcifes ; a Defect in the Nerves, in having their natural Faculry abolifli'd, or fufpended, as in a Lethargy, and Apoplexy ; and, according to Silvius, by a grofs, vifcid Saliva, or a thick Bile", amend- ing out of the fmall Guts into the Stomach. DISTEMPER, in Medicine. See Disease. Distemper, is alfo us'd in Painting, for the working up of Colours with fomething elfe befides bare Water, or Oil. See Colour.

If the Colours are prepar'd with the former of thefe, that Kind of Painting is call'd Limning; and if with Oil, it is call'd Painting in Oil, and limply Painting. See Lim- ning, and Painting.

If the Colours are mix'd with Size, Whites of Eggs, or any fuch proper glutinous, or unctuous Subfiance, and not with Oil, they then fay, it is done \i\1)iflempsr ; as the admirable Cartons at Hampton-Court.

DISTENSION, the A3 of flretching a Thing ; alfo the State of a Thing violently llretch'd, and diftended.

The Calculus is a hard, folid, (So. Body, cauling a Stu- por, Obllructions, and Detentions. Dcgori.

DISTICH, a Piece of Poetry, the Senfe whereof is com- prehended in two Lines.

There are excellent Morals in Cato's Uifflichs. Sec Vigtzevl de Marmlle on the Dillichs e/Cato, T. 1. f>. 54, 55,

Hexameter, and Pentameter Verfes, othcrwifc call'd Ele- giacks, are difpo&d in Diftichs. See Verse.

D1ST1CHIAS1S, in Medicine, a Diforder of the Eye-lids, wherein, inftead of one, they have two Rows oi Cilia, or Hairs. See Cilia.

In the WfticMafis, over the common, and natural Hairs, there grows another extraordinary Row, which frequently eradicates, and tears up the former, and pricking the Mem- brane, immediately inverting the Eye, occafions Pain, and draws Dcfluxions upon it.

'Tis cur'd, by plucking up the fecond Row of Hairs with

Nippers, and burning the Pores, out of which they iffued.

The Word is form'd of  ,- >

DISTILLATION, or DEST1LLATION, inChymiftry, and Pharmacy, the Art, or Aft of feparating, or drawing off the fpirituous, aqueous, oleaginous, or faline Parts of a mix'd Body from the grofler, and more terreffrial Parrs, by means of Fire ; and collecting, and condenfing them again by Cold. See Heat, i$c.

The VJfe ot 1)iftillation is very great ; it being by means hereof, that Waters, Spirirs, Eifcnces', andExtrafts are chiefly made. See Water, Spirit, iSc.

Hiftillation is ufually perform 'd by means of Fire rais'd to a greater, or leffcr Degree, as Circumftancc leaft require. See Fire.

The Fire is either applied immediately to the VefTels where- in the Matters are to be diftilled ; or it is applied mediately, by means of Water, Sand, Iron-filings, 5?c. Thefe different Methods of applying the Fire, are call'd 'Baths, Salnei ;

Sal-