Page:Cyclopaedia, Chambers - Volume 1.djvu/341

 CHA

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CHA

£ba%rin'y but this laft is diftinguiili'd by its peeling off, which the firft does nor.

CHAIN, Catena, a Scries of feveral Rings, or Links, fltted into one another. See Link.

There are Claim of divers Matters, Sizes, Forms, and for divers Ufes. Ports, Rivers, Streets, &C\ areclos'd with Iron Chains ; Rebellious Cities are punifh'd by taking away their Chains and Barriers.

The Arms of the Kingdom of Navarre are Chains Or, in a Field Gules. The Occasion hereof is referr'd to the Kings of Spain leagu'd againft the Moors $ who having gain'd a celebrated Victory againft 'em in 121:, in the Distribution of the Spoils, the magnificent Tent of 'MirUl- mumin fell to the King of Navarre ; as being the firft that broke and fore'd the Chains thereof.

A Gold Chain, is one of the Ornaments or Badges of the Dignity of a Lord-Mayor of London - 7 and remains to the Perfon, after his being diverted of that Magiftrature, as a Mark he has pafs'd the Chair. Sec Mayor, and Al- derman.

Something like this, Chorier obferves, obtain'd among the antient Gauls ; The principal Ornament of their Per- form in Power and Authority was a Gold Chain, which they wore on all Occasions ; and even in Battel, to diliinguifh 'em from the common Soldiers. Hift. de ^Dauph. Lib. III. p. 130.

Chain is alfo a kind of little TifTuc, ferving to hang AVarches, Tweezer- Cafes, and other valuable Toys upon. See "Watch.

The Invention of this piece of curious Work is owing to the Engitjh 5 whence, in foreign Countries, it is deno- minated the Etfglijh Chain. 'Tis but of very late Years that Foreigners have undertook to imitate 'em, and yet with no extraordinary Succefs ; thofe of 'Paris have come nearelK Thtzfe Chains are ufually either of Silver or Gold, fome of gilt Copper 5 the Thread or Wire of each Kind to be very fine.

For the Fahrick, or Maki?ig of thefe Chains ; a Part of the Wire is folded into little Links of an oval Form; the longeft Diameter about three Lines, the /horteft one. Thefe, after they have been exactly folder'd, are again folded into two j and then bound together, or interwove, by means of feveral other lirtle Threads of the fame thicknefs ; Ibmc whereof, which pafs from one end to the other, imitate the Warp of a Stuff} and the others, which pafs tranfverfe, the Woof. There are at leaft four thoufand little Links in a Chain of four Pendants 5 which are, by this means, bound fo equally, and withal fo firmly together, that the Eye is deceiv'd, and takes the whole to confift of one en- tire Piece.

Cn^iti-Shot, in War, two Bullet?, or rather half-Bul- lets, link'd together by a Chain ; their ufe at Sea is to Shoot down Yards, or Malls ; or to cut the Shrouds, or any other Rigging of a Ship. Cu Kin J P ump. See Pump, and 'BvR-'Pump. Chain, in Surveying, is a Meafure confiiling of a cer- tain Number of- Links of Iron Wire, ufually 100 ; ferving to take the Dimensions of Fields, £$c. by : See Mea- sure, and Surveying.

This F. Merfenne takes to be the Arvipendium of the Ancients. See Acre.

The Chain is of various Dimenfions, as the Length or Number of Links varies : That commonly us'd in mea- furing Land, call'd Guntefs Chain, is in Length four Poles, or Perches j or 66 Yards, or 100 Links 5 each Link being &ven Inches ~\. See Perch, Link, Yard, &c.

That ordinarily us'd for large Diftances, is in length 100 Feet ; each Link one Foot.

For fin all Parcels, as Gardens, $$c. is fome times us'd a fmall Chain of one Pole, or itf Foot and a half length ; each Link one Inch ^1^.

Some, in lieu of Chains, ufe Ropes 5 but thefe are liable to feveral Irregularities ; both from the different Degrees of Moifture, and of the Force which Stretches them. Schmoenterus, in his Practical Geometry, tells us, he has obferv'd a Rope \6 Foot long, redue'd to 1 5 in an Hour's time, by the mere failing of a Hoar Frolt. To obviate thefe Inconveniencies, Wolfius directs, that the little Twills whereof the Rope conflfts, be twifled contrary ways, and the Rope dipp'd in boiling hot Oil, and when dry, drawn thro melted Wax. A Rope thus prepar'd, will not get or lofe any thing in Length, even tho kept under Water all Day.

Ufe of the Chain in Survey 'wg. The manner of applying the Chain in meafuring Lengths is too popular to need Dcfcription. In entering down the Dimenfions taken by the Chain, the Chains and Links are fep«irated by a Dot : Thus a Line tf 3 Chains 5 5 Links long, is wrote 63.55. If the Links be Short of 10, a Cy- pher is prefix'd; thus 10 Chains, 8 Links, are wrote 10.08. To find the Area of a Field, ike. the 'Dimcnfibus where- (f-arcghsn in Chains and Links, ill, Multiply the Lines

by one another, according to the Rules given under A- rea 5 and from the Product cut off live Figures towards the Right : fo thofe remaining on rhc Left will be Acres* See Acre, idly, Multiply the rive Figures cut off by 4 - and cutting off Sive again from the Product on the Right , thofe remaining on the Left will be Roods. Sec Rood. Laftly, Multiply the five thus cut off by 40 ; and cutting off five, as before, on the Right, thofe remaining on the Left are fquare 'Perches. See Perch.

To take an Angle DAE, (Tab. Surveying, Fig. 1.) hy the Chain : Meafure a fmall Dillance from the Vertex A along each Leg, v.g. to A and c; then meafure the Dif- tance dc : To lay this down, draw A E at plcafure, and from your Scale fct off the Distance meafur'd on it. See Scale.

Then, taking in your Compaffes the Length meafur'd on the other Side, on the Vertex A, as a Centre, defcribe an Arch £ c'; and on the Point c, as a Centre, with the meafur'd Diftance of c d, defcribe another Arch ah. Thro the Point where this interfects the former Arch, draw a Line A D. So is the Angle plotted $ and its Quantity, if rcquir'd, may be meafur'd on a Line of Chords. See Chord.

To take the 'Plan or 'Plot of any 'Place, as A B C D E, CFig. 2.) by the Chain. Draw a rough Sketch of the Place by Eye ; and meafuring the feveral Sides AB, B C, CD, D E, enter down the Length on the refpective Lines : then if the Plan be to be taken within fide of the Place, inilead of meafuring the Angles, as before, measure rhe Diagonals A B, B D. Thus will the Figure be redue'd in- to three Triangles, whofe Sides are all known, as in the former Cafe 3 and may be laid down on Paper, according to the Method above.

If the Plan be to be taken without fide the Place, the Angles mult be taken thus 5 v.g. for the Angle BCD, pro- duce the Lines B C and C D to any certain equal Diltance, v. g. to a and h, five Chains meafure the Diltance of a b. Thus have you an Ifoiceles Triangle C a h, wherein the Angle a C h ™ B C D its opposite one is had : thus is the Quantity of BCD found, and the Angle laid down as before.

By the Chain to find the T)ifiance bet-ween two Objects inacccjjlble in refpect of each other. From fome Place, as C, (Tig. JO whence the common Diftance to each Ob|ect A and B, is acceSIible in a right Line ; meafure the Diftance C A, which fuppofe 50 Chains $ and continue the Line to D, viz. 50 more: Meafure alfo B C, which fuppofe 30 Chains ; and produce the Line to E, viz,. 30 more. Thus will be form'd the Triangle CDE, equal and fimilar to the Triangle ABC; co.ifequently the Diltance D E, be- ing meafur'd, will give the inacceSlible Diltance requir'd.

Sy the Chain to find the ^Di fiance of an inaccejfible Ob- ject, v.g. the Breadth of a River. On one fide piace a Pole, four or five Foot high, perpendicularly, havin? a Slit a-top, with a Strait Piece of Wire, or the like, two or three Inches long, put thro the fame. This is to be flipp'd up or down, till, looking along it, you find it point full on the other Side of the River; then turning rhe Pole with the Wire in the fame Direction, obferve the Point on the dry Land, to which it points when look'd along as before : meafure the Diftance from the Pole to this laft Point ; 'tis the fame with that of the firft requir'd. See Surveying, Protracting, Plotting, Theodolite, £-?c

CHAIR, Cathedra, was antiently us'd for the Pulpit, or Suggefium, whence the Prieft fpokc to the People. See Pulpit, and Cathedra.

It is ftill appiy'd to the Place whence Profeffors and Re- gents in Universities deliver their Lectures, and teach the Sciences to their Pupils : Thus, we fay, The Profeffcr's Chair \ the DoBofs Chair, Sec. See Professor, &c.

Curule Chair, was an Ivory Seat plac'd on a Car, where- in were feated the firft Magistrates of Rc?ne, and thofe to whom the Honour of a Triumph was granted. See Curule.

Chair is alfo us'd among the Romanifis for fome Feafts, held antiently in Commemoration of the Translation of the See or Seat of the Church, by St. 'Peter.

The perforated Chair, wherein the new-elected Pope is plac'd, F. Mabillon obferves, is ftill to be feen at Rome ; but the Origin thereof he does not attribute, as is com- monly done, to the Adventure of Pope Joan ; but fays there is a Myftery in it ; and 'tis intended, forfooth, to explain to the Pope thole Words of Scripture, that God draws the 'Poor from out of the Dufi a7id Mire.

CiiMK-Man, the Prefident, or Sneaker of an Affembly, Company, &c. See President, $£c.

The C11A.1K- Man of a Committee, &c. See Commit- tee, £s?c.

CHAISE, a fort of light open Chariot, or Calajb. See Coach, and Chariot.

CHALASTIC Medicines, are fuch as have the Faculty of foftcning, and relaxing the Parts; when> on account of their

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