Encyclopaedia Britannica [10, 3 ed.]

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X

BRirANNICA;

ENCYCLOPJEDIA

D I C T I 6 NARY O F ARTS,

SCIENCES, AND

MISCELLANEOUS LITERATURE; Conftm6ted on a PLAN, BY WHICH

THE DIFFERENT SCIENCES AND ARTS Are digefted into the

TREATISES

FORM

of

OR

Diflind

SYSTEMS,

COMPREHENDING

The

THEORY, and PRACTICE, of according to the Lateft Difcoveries and Improvements; FULL EXPLANATIONS GIVEN OF THE

HISTORY,

each,

VARIOUS DETACHED PARTS OF KNOWLEDGE, WHETHER RELATING TO

NATURAL

and

ARTIFICIAL

Objefts, or to Matters

CIVIL, MILITARY, COMMERCIAL,

Including

ELUCIDATIONS

ECCLESIASTICAL,

'tic.

of the mod important Topics relative to RELIGION, and the OECONOMY of LIFE :

MORALS,

MANNERS,

TOGETHER

A

DESCRIPTION

WITH

of all the Countries, Cities, principal hlountains, Seas, Risers, throughout the WORLD;

A General HISTORY, Ancient and Modern^ of the different Empires, Kingdoms, and States; AND

An Account of the LIVES of the moft Eminent Perfons in every Nation, from the earlieft ages down to the prefent times. Compil'd from the writings of the b'f Author,, inftveral languages; tb' mof approved DiHionaries, as well of general fsknee as of its particular branches ; tie 'Iranjailions, Journals, and Mem sirs, of learned Societies, both at Lome and abroad: the MS. Letlures of Eminent Prcfcjfori on different feienus ; and a variety of Original Materials, furniJbeJ by asi Extenfsve Correfpondence. ‘THE THIRD EDITION, IN EIGHTEEN VOLUMES, GREATLY 1MFR0\ ED.

ILLUSTRATED WITH FIVE HUNDRED AND FORTY-TWO COPPERPLATES. VOL. iNDoerr

DISCANT,

KY

X.

AMENT

UEMiNtsss PKRirr.

EDINBURGH. PRINTED FOR A. BELL AND C. MACFAROi* ^ AR»

MDCCXCYU.

dntcteu (n Stationers |>an in Cerms of tfte aa of parliament. —-

»

✓

ENCYCLOPEDIA

BRITANNICA.

s

LET

L E

T a town of Suffolk in * JLj England, feated on the fea-fhore, 117 miles north-

L’Eftraf’e ge

or

I-EOSTOFF,

weft of London. It is concerned in the fiftieries of the North-fea, cod, herrings, mackerels, and fprats; has a church, and a diffenting meeting-houfe ; and for its fecuritr, fix eighteen-pounders, which they can move as occafion requires; but it has no battery. The town confifts of 500 houfes; but the ftreets, though tolerably paved, are narrow. It has a market on Wednefdays, and two fairs in the year for petty chapmen. The coaft is there very dangerous for ftrangers. L’ESTRANGE (Sir Roger), a noted writer in the 17th century, was defeended from an ancient family, feated at Hunftanton-hall in the county of Norfolk, where he was born in 1616, being the youngeft fon of Sir Hammond L’Eftrange baronet, a zealous royalift. Having in 1644 obtained a commiflion from King Charles I. for reducing Lynn in Norfolk, then in poffeftion of the parliament, his defign was difeovered, and his perfon feized. He was tried by a court martial at Guildhall in London, and condemned to die as a fpy ; but was reprieved, and continued in Newgate for fome time. He afterward went beyond fea ; and in Auguft 1653 returned to England, where he applied himfelf to the proteftor Oliver Cromwell, and having once played before him on the bafs-viol, he was by fome nicknamed Oliver's Jiddler. Being a man of parts, mafter of an eafy humorous ftyle, bpt withal in narrow circiimftances, he fet up a ncwfpapir, under the title of The Public Intelligencer, in 1663 ; but which he laid down, upon the publication of the firft London gazette in 1665, having been allowed, however, a confideration by government. Some time after the Popifti plot, when, the Tories began to gain the afeendant over the Whigs, he, in a paper called the Obfervotor,, became a zealous champion for the former. He was afterwards knighted, and ferved in the parliament called by King James II. in 1685. ^ut tilings taking a different turn in that prince’s reign, in point of liberty of confidence, from what moft people expeftcd, our author’s Olfcrvators were difufed as not at all fuiting the times. However, he continued licenfer of the prefs till King William’s acceffion, in whofe reign he met with fome trouble as a difaffedhed perfim. However, he went to his grave'in peace, after he had in a manner furvived his intelle&uals. He publifhed a great many political trads, and tmrrfiated feveral works from the Greek, Latin, and Spanifii; vi%. Jofephus’s works, Cicero’s Offices, Seneca’s Morals, Erafmus’s Colloquies, Efop’s Fables, and Bonas’s Guide to Eternity. The charader of his ftyle has been varioufly reprefented ; his language being obferved by VOL.X. Parti.

fome to be eafy and humorous, while Mr Gordon fays, “ that his produdions are not fit to be read by any who have tafte or good-breeding. They are full >i~ phrafes picked up in the ftreets, and nothing can be more low or naufeous.” LESTWEITHEL, a town of Cornwal in England, about 229 miles diftant from London. It is a well-built town, where are kept the common gaol, the weights and meafures for the whole ftannary, and the county courts. It ftands on the river Foy, which brought up veffels from Fowey, before it was choaked up with fand coming from the tin-mines, and therefore its once flourifhing trade is decayed ; but it holds the bufhelage of coals, fait, malt, and corn, in the town of Fowey, as it does the anchorage in its harbour. It was made a corporation by Richard earl of Cornwal when he was king of the Romans, and has had other charters fince. It confifts of feven capital burgeffes (whereof one is a mayor), and 17 afiiftants or common council. It is part of the duchy of Corfwal, to which it pays L. 11:19:10a year for its liberties. Its chief trade is the woollen manufa&ory. Its church has a fpn e, the onlj one except that ofHelfton in the county. Its market is Friday, and its fairs are three. It firft returned members to parliament in the 33d of Edward I. They are chofen by their burgeffes and afIrflants. It was anciently the /hire-town, and the knights of the fiiire are ftill chofen here. LETCHLADE, a town ofGloucefterfiiirc,9omile6 from London, on the borders of Oxfordfhire and Berks, and the great road to Gloucefter; had anciently a nun-nery, and a priory of black canons. In this pari/h is Clay-hill. The market is on Tuefday; and it has two fairs. It is fuppofed to have been a Roman town: for a plain Roman road runs from hence to Cirencefter; and by digging in a meadow near it fome years ago, an old building was difeovered, fuppofed to be a Roman bath, which was 50 feet long, 40 broad, and 4 high, lupported with TOO T ick pillars, curioufly inlaid with ftones of divers colours of tefferaic work. The Leech, the Coin, the Churn, and ffis, which all rife in the Cotfwould-hill, joi'i here in one full ftream, and become one river, called the Thames, which begins here to be navigable, and barges take in butter, cheefe, and other goods, at its quay for London. LETHARGY, in medicine (from oblivion, and a r,% f‘ numlnefs, lazinefs), a difeafe confitling of a profound drowfinefs or fieepinefs, from which the patient, can fcarce be awaked; or, if awaked, he remains ftupid, without fenfe or memory, am! prefently finks again into his former Deep. See Mtmciw.-Index. LETHARGY, in farriery. See there, ^ 9. ■ * A LETHE,

L

.H _urgy‘f

LET-

{4

LET Letter.

LETHE, in the ancient mythology, one of the vented them, and among what^people they were firft JLethe II rivers of hell, fignifying oblivion or forgctfulnefs ; its in ufe, there is ftill room to doubt : Philo attributes Letter. ! waters having, according to poetic fiction, the peculiar this great and noble invention to Abraham ; Jofephus, quality of making thofe who drank them forget every St Irenaeus, and others, to Enoch ; Bibliander, to Adam ; Eufebius, Clemens Alexandrinus, Cornelius thing that was paft. LETI (Gregorio), ?.n eminent Italian writer, was Agrippa, and others, to Mofes; Pomponius Mela, defeended of a family which once made a conliderable Herodian, Rufus Feftus, Pliny, Lucan, &c. to the figure at Bologna: Jerom, his father, was page to Phoenicians; St Cyprian, to Saturn ; Tacitus, to the prince Charles de Medicis; ferved fome time in the Egyptians ; fome, to the Ehtiopians ; and others, to troops of the grand duke as captain of foot; and the Chinefe : but, with refpetSt to thefe laft, they can fettling at Milan, married there in 1628. He was af- never fee intitled to this honour, fince all their characterward governor of Almantea in Calabria, and died ters are the figns of words, formed without the ufe of at Salerno in 1639* Our author was born at Milan letters ; which renders it impoffible to read and write in 1630, lludied under the Jefuits at Cofenza, and their language without a vaft expence of time and was afterward fent by an uncle to Borne, who would trouble ; and abfolutely impoffible to print it by the have him enter into the church ; but he being averfe help of types, ror any other manner but by engraving, to it, wrtit into Geneva, where he ftudred the govern- or cutting in w ood. See PRINTING. There have been alfo various conje&ures about the ment and the religion there. Thence he went to Laufanne ; and contracting an acquaintance with John different kinds of letters ufed in different languages : Anthony Guerin, an eminent phyfician, lodged at his thus, according to Crinitus, Mofes invented the Hehoufe, made profefiion of the Calviniit religion, and brew' letters ; Abraham, the Syriac and Chaldee ; the married his daughter. He fettled at Geneva; where Phoenicians, thofe of Attica, brought into Greece by he fpent almoft twenty years, carrying on a correfpon- Cadmus, and from thence into Italy by the Pelafdence with learned meo, efpecially thofe of Italy. Some gians ; Nicoftrata, the Roman ; Ills, the Egyptian ; contefts obliged him to leave that city in 16795 upon and Vulfilas, thofe of the Goths. It is probable, that the Egyptian hieroglyphics which he went to France, and then into England, where were the firft manner of writing : but whether Cadmus he was received with great civility by C harles II. who, atfter his firft audience, made him a prefent of a thou- and the Phoenicians learned the ufe of letters from the fand crowns, with a promife of the place of hiitorio- Egyptians, or from their neighbours of Judea or Sagrapher. He wrote there the Hiilory of England ; maria, is a queftion ; for fince fome of the books of but that work not pleafing the court on account of his the Old Teftament were then written, they are more too great liberty in writing, he was ordered to leave likely to have given them the hint, than the hieroglyBut wherefoever the Phoenicians, the kingdom. He went to Amfterdam in 1682, and phics of Egypt. learned this art, it is generally agreed, that Cadmua. was honoured with the place of hiiloriographer to that city. Ele died fuddenly in 1701. He was a man of the fon of Agenor firft brought letters into Greece ; indefatigable application, as the multiplicity of his whence, in following ages, they fpread over the reft works Puow. The principal of thefe are, 1. 1 he uni- of Europe. See ALPHABET and WRITING. Letters make the firft part or elements of grammar ; verfal monarchy of Louis XIV. 2. The life of Pope Sixtus V. 3. The life of Philip II. king of Spain. an affemblage of thefe compofe fyllables and words, 4. The life of the emperor Charles V. 5. 1 he life and thefe compofe fentences. The alphabet of every of Elizabeth, queen of England. 6. The hiitory fif language confifts of a number of letters, which ought Oliver Cromwell. 7. The hiftory of Great Britain, each to have a different found, figure, and ufe. As the difference of articulate founds was intended to ex5 vols i2mo. 8. The hiftory of Geneva, &c.. LETRIM, a county of Ireland, in the province of prefs the different ideas of the mind, fo one letter was Connaught, 44 miles in length and 17 i*1 breadth ; originally intended to fignify only one found, and not,, bounded on the eaft and north-eaft by Cavan and Fer- as at prefent, to exprefs fometimes one found and managh, by Sligo and Rofcommon on the weft and Jjmctimes another ; which pra&icc has brought a great foutb-weft, and by Longford on the eaft and fouth-eaft. deal of confufion into the languages, and rendered the It is a hilly country, with rank grafs, which feeds a learning of the modern tongues much more difficult great number of cattlp. The chief town is Letrim, than it would otherwife have been. This confiderafeated not far from the river Shannon. It contains tion, together with the deficiency of all the known al4000 houfes, 21 pari (lies, 5 baronies, 2 boroughs, and phabets, from their wanting fome letters to exprefs certain founds, has occafioned feveral attempts towards fends 6 members to parliament. LETTER, a chara&er ufed to exprefs one of the an univerfal alphabet, to contain an enumeration of fimple founds of the voice ; and as the different fimple all fuch fingle founds or letters as are ufed in any lanfounds are expreffed by different letters, thefe, by be- guage. See ALPHABET. Grammarians diftinguifh letters into vowels, confoing differently compounded, become the viiible figns nants, mutes, liquids, diphthongs, and charncteri-•r ehara&ers of all the modulations and mixtures of ftics. They are likewife divided into capital and i'mall founds ufed to exprefs our ideas in a regular language ; (See LANGUAGE). Thus, as by the help of fpeech we letters. They are alfo denominated from the ftiape render our ideas audible ; by the afliftance 01 letters we and turn of the letters ; and in writing are diftinguithrender them vifible, and by their help we can wrap up ed into different hands, as round-text, German-text, our thoughts, and fend them to the molt diftant parts round-hand, Italian, &c. and in printing, into Roman, of the earth, and read the tranfa&ions of different ages. Italic, and black letter. The term L&TTtR; or Type, among printers, not onAs to the firft letters, what they were, who hr ft i^'

LET ^

Hoard's %raury.

[ 3

1

L

El T

ly Includes the CAPITALS, SMALL CAPITALS* and Accordingly Cicero fays ; u In writi g letters, we Letter iniall letters, but all the points, figures, and other make ufe of common words and exprefiions.” And ^ marks call and ufed In printing; and alfo the large Seneca more fully, “ I would have my letters to be ornamental letters, cut in wood or metal, which take like my difeourfes, when w'e either rfit or walk toplace of the illumined letters ufed in manufcripts. The gether, undudied and eafy.” And what prudent letters ufed in printing are call at the ends of fmall man, in his common difeourfe, aims at bright and pieces of metal, about three quarters of an inch in drong figures, beautiful turns of language, or lalength ; and the letter being not indented, but raifed, boured periods ? Nor is it always requifite to attend eafdy gives the impreffion, when, after being blacked to exatft order and method. He that is mader of with a glutinous ink, paper is clofely prelfed upon it. what he wmites, will naturally enough exprefs hisi See the articles PRINTING and TYPE. A fount of thought without perplexity and confufion ; and more letters includes fmall letters, capitals, fmall capitals, than this is feldom neceffary, efpecially in familiar points, figures4, fpaces, &c.; but befides, they have dif- letters. ferent kinds of two-line letters, only ufed for titles, Indeed, as the fubjefts of epidles are exceedingly* and the beginning of books, chapters, &c. See FOUNT. various, they will neceflarily require fome variety in LETTER is alfo a writing addrelfed and fent to a the manner of expreflion. If the fubje& be fomething perfon. See EPISTLE. . weighty and momentous, the language (hould be' T. he art of epiftolary writing, ai the late tranflator drong and folemn ; in things of a lower nature, more of Pliny s Letters has obferved, was elleemed by the fiee and eafy; and upon lighter matters, jocofe and Romans in the number of liberal and polite accom- pleafant. In exhortations, it ought to be lively and pli lliments ; and we find Cicero mentioning with great vigorous; in confolations, kind and compafiionatc; and pleafule, in ictne of his letters toAtticus, the elegant in advifing, grave and ferious. In narratives, it (hould .Ipecimen he had received from his fon of his genius be clear and didind ; in requeds, moded; in commenin this way. It feems indeed to have formed part of dations, friendly; in profperity cheerful, and mournful their education ; and, in the opinion of Mr Locke, in adverfity. In a wrord, the dyle ought to be acit well deferves to have a (hare in ours. “ The wri- commodated to the particular nature of the thing about “ ting of letters (as that judicious author obferves) which it isconverfant. “ enters fo much into all the occafions of life, that no Befides, the different chara&er of the perfon, to gentleman can avoid (hewing himfelf in compofi- whom the letter is w'ritten, requires a like difference c< tions of this kind. Occurrences will daily force him in the modes of expreffion. We do not ufe the fame to make this ufe of his pen, which lays open his language to private perfons, and thofe in a public da“ breeding, his fenfe, and his abilities, to a feverer tion; to fuperiors, inferiors, and equals. Nor do we ** examination than any oral difcourfe.,, It is to be exprefs Ourfelves alike to old men and young, to the Pondered we have fo few writers in our own language grave and facetious, to courtiers and philofophers, who deferve to be pointed out as models upon fuch an to our friends and drangers. Superiors are to be adoccafion. After having named Sir William Temple, it dreffed to with refpedl, inferiors with courtefy, and would perhaps be difficult to add a fecond. The elegant equals with civility; and every one’s chara&er, dawriter of Cowley’s life mentions him as excelling in tion, and circumdances in life, with the relation we this uncommon talent; but as that author declares dand in to him, occafions fome variety in this refpedf. himfelf of opinion, “ That letters which pafs between But when friends and acquaintances correfpond by familiar friends, if they are Written as they fhould be, letters, it carries them into all the freedom and goodcan fcarce ever be fit to fee the light,’" the world is humortr of converfation ; and the nearer it refembles deprived of what no di ubt w'ould have been well worth that, the better, fince it is defigned to fupply the room its infpe&ion. A late di(tinguifhed genius treats the of it. For when friends cannot enjoy each other* very attempt as ridiculous, and profeffes himfelf “ a company, the next fatisfadfion is to converfe with mortal enemy to what they call aJine letter.” His each other by letters. Indeed, fometimes greater averfion however was not fo (Irong, but he knew to freedom is ufed in epidles, than the fame perfons conquer it when he thought proper; and the letter would have taken in difeouriing together ; becaufe, which clofes his correfpondence with bifhop Atterbury as Cicero fays, “ A letter does not blu(h.” But (till is, perhaps, the mod genteel and manly add refs that nothing ought to be faidin a letter, which, confidered ever was penned to a friend in difgrace. The truth in itfelf, would not have been fit to fay in difeourfe ; is, a fine letter does not confirt in faying fine things, though modedy perhaps, or fome other particular but in exprefiing ordinary ones in an uncommon man- reafon, might have prevented it. And thus it frener. It is the proprie cotnmunia die ere, the art of giving quently happens in requeds, reproofs, and other cirgrace and elegance to familiar occurrences, that con- cumdances of life. A man can a(k that by writing, (litutes the merit of this kind of writing. Mr Gay’s which he could not do by wrords, if prefent; or blame letter, conceming the two lovers who W’ere ftruck wrhat he thinks amifs in his friend with greater liberty dead with the fame flafh of lightning, is a mader-piece when abfent, than if they were together. From hence of the fort ; and the (pecimen he has there given of it is eafy to judge of the (itnefs of any exprefiion to his talents for this fpecies of compofition makes it dand in an epidle, only by confidering, whether the much to be regretted we have not more from the fame fame wray of (peaking would be proper in talking with hand. the fame perfon. Indeed, this difference may be al0/the Style of Epi/lolary Compvjition. Purity in the lowed, that as perfons have more time to think, when choice of words, and judntfs of condru&ion, joined they write, than when they fpeak ; a greater accuwith perfpicuity, are the chief properties of this llyle. racy of language may fometimes be expected in one,

A 2

than

LET

L 4. ]

LEU

LEVANT, in geography, fignifies any country Levant Letter, than the other. However, this makes no odds as to fituated to the ead of us, or in the eaftern fide of any Leu^ta> I,etiucr. the kind of ilyle; for every one would choofe to fpeak as correftly as he writes, it he could. And there- continent or country, or that on which the fun rifes. LEVANT, is alfo a name given to the eadern part fore all fuch words and exrpreflions, as are unbecoming" in converfation, fhould be avoided in letters ; and of the Mediterranean fea, bounded by Natolia or the a manly fimplicity free of all affedfation, plum, but Lefier Afia on the north, by Syria and Paledine on decent and agreeable, Ihould run through the whole. the ead, by Egypt and Barca on th^iouth, and by This is the ufual ftyle of Cicero’s epiitles, in which the ill and of Candia and the other part of the Medithe plainnefs and fnnplicity of his diction is accom- terranean on the wed. LEVATOR, in.anatomy, a name given to feveral panied with fomething fo pleafant and engaging, that mufcles. See ANATOMY, Table of the Mufcles. he keeps up the attention of his reader, without fufLEUCA, in antiquity, a geographical meafure of fering him to tire. On the other hand, Pliny’s llyle is fuccinft and witty ; but generally fo full of turns length in ufe among the later Gauls; which, accordand quibbles upon the found of words, as apparently ing to Jornandes, who calls it leuga, contained fifrender it more lliff and affe£ted than agrees with teen hundred paces, or one mile and a half. Hence converfation, or than a man of fenfe would choofe in the name of league, now reckoned at three miles ; in difeourfe, were it in his power. You may in fome the lower age, called leuva. LEUCADENDRON, in botany : A genus of the meafure judge of Pliny’s manner, by one ihort letter monogynia order, belonging to the tetrandria clafs of to his friend, which runs thus : “ How fare you ? As I do in the country? pleafantly ? that is, at leifure? plants; and in the natural method ranking under the For which reafon 1 do not care to write long letters, 48th order. Aggregate. The florets are tripetalous, but to read them ; the one as the elfecl of nicenefs, with one petal of" each trifid ; the receptacle is a little and the other of idlenefs. For nothing is more idle villous; there is no proper calyx ; the anther* are aithan your nice folks, or curious than your idle ones. med coalited. LEUCADIA, formerly called Neniit, a peninFarewell.” Ever/ fentence here conlills of an antifula of Acarnania, (Homer); but afterwards, bythefis, and a jingle of words, very different from the ityle of converfation, and plainly the effeft of ftudy. cutting through the peninfula, made an ifland, as it But this was owing to the age in which he lived, at is at this day, called St Maura. LEUCAS, (anc. geog.), formerly called iLeritos which time the Roman eloquence was funk into puns, and Neritum, a town ot Leucadia or Leucas ; fituated and an affectation of wit; for he was otherwife a man near a narrow neck of land, or iithmus, on a hill faof fine fenfe and great learning. LETTER of Attorney, in law, is a writing by which cing the ead and Acarnania: the foot or lower part one pevfon authorifes another to do fome lawful act of the town was a plain lying on the fea by which in his Head ; as to give feifin of lands, to receive debts, Leucadia was divided from Acarnania, (Livy) ; though Thucydides places Leucas more inward in the ifland, fue a third perfon, &c. The nature of this inllrument is to transfer to the which was joined to the continent by a bridge. 11 perfon to whom it is given, the whole power of the was an illuflrious city, the capital of Acarnania, and maker, to enable him to accomplifh the act intended the place of general afiembly. LEUCATA, or LEUCATE, (anc. geog.); a proto be performed. It is either general or fpecial : and fometimes it is made revocable, which is when a bare montory of Leucadia according to Strabo, a white authority is only given ; and fometimes it is irrevo- rock proje&ing into the fea towards Cephalenia, on cable, as where debts, experiment, when the thermometer Hands at the fame This inflrument may be ufed on other occafions, by height as before. The water is poured out when placing the ends of its two branches on a plane ; for the inflrument is earned ; which one may do conve- when the thread plays perpendicularly over th^ middle niently by means of the wooden frame, which is fet divifion of the quadrant, that plane is affuredly level, upright by the three ferews, S, S, S, fig. 4. and To ufe it in gunnery, place the two ends on the piece a line and plummet P P, fig. 5. At the back part of of artillery, which you may raife to any propofed the wooden frame, from the piece at top K, hangs the height, by means of the plummet, whofc thread will plummet P, over a brafs point at N; M m are brackets give the degree above the level. to make the upright board K N continue at right Carpenter's and Pavior's IJF.Vm, confifls of a long angles with the horizontal one at N. Fig. 6. reprefeuts ruler, in the middle whereof is fitted', at right angles, a front view of the machine, fuppofing the fore part another fomewhat bigger, at the top of which i* of the tin-veffel tranfparent; and here the brafs-focket faflened a line, which, when it hangs over a fiducial of the recurve-tube, into which the ball is ferewed, has line at right angles with the bafe, fhows that the faid two wings at 11, fixed to the bottom, that the ball bafe is horizontaL Sometimes this Level is all of one may not break the tithe by its endeavour to cmeige board. Fig. 8* when the water is poured in as high as^/;. Gunner's LF-MI, for levelling cannons and mortars, After the Dodlor had contrived this machine, he confifls of a triangular brafs plate, about four inches, confidered, that as the tube is of a very fmall bore, if high, fig. 9. at the bottom of which is a portion the liquor fliould rife into the ball at A (fig. 3.) in car- of a circle, divided into 4J degrees; which number rying the inflrument from one place to another, fome is fufficient for the higheft elevathm of cannons and of it would adhere to the Tides or the ball A, and up- mortars, and for giving fhot the greatefl range : on on its defeent in making the experiment, fo much the centre of this fegment of a circle is ferewed a piece might be left behind, that the liquor would not be of brafs, by means of which it may be fixed or ferewed high enough at D to fhow the difference of the level: at pleafure : the end of this piece of brafs is made fo therefore, to prevent that inconveniency, he contrived as to ferve for a plummet and index, in order to fhow a blank ferew, to fhut up the hole at A, as foon as one the different degrees of elevation of pieces of artillery, experiment is made, that, in carrying the machine, the This inftrument has alfo a brafs foot, to fet upon canair in A may balance that in C, fo that the liquor nons or mortars, fo as, when thofe pieces are horizonfhall not run up and down the tube, whatever degree tal, the inflrument will be perpendicular. The foot of heat and cold may adt upon the inflrument, in go- of this inftrument is to be placed on the piece to be ing from one place to another. Now, becaufe one ex- elevated, in fuch a manner, as that the point of the periment may be made in the morning, the water may plummet may fall on the proper degree : this is what be fo cold, that when a fecond experiment is made at they call levelling the piece. noon the water cannot be brought to the fame degree Mafon's LsrRLy is compofed of three rules, fo joinof cold it had in the morning ; therefore, in making ed as to form an ifofceles-redlangle, fomewhat like a the firfl experiment, warm water mufl he mixed with Roman A ; at the vertex whereof is faflencd a thread, the cold, and when the water has flood fome time, be- from which hangs a plummet, that partes over a fidufore it comes to be as cold as it is likely to be at the cial line, marked in the middle of the bafe, when the warmell part of that day, obferve and fet down the de- thing to which the level is applied is horizontal; but gree of the thermometer at which the fpirit Hands, declines from the mark, when the thing is lower onand hkewife the degree of the water in the barometer the one fide than op the other. at D ; then ferew on the cape at A, pour out the waPlumb or Pendulum LF.rKL, that which fhows the ter, and carry the infirument to the place whofe level horizontal lines by means of another line perpendicular you would kjiow; then pour in your water, and when to that deferibed by a plummet or pendulum. This the thermometer is come to the fame degree as before, infirument, fig. 10. confilts of two legs or branches, open the ferew at top, and obferve the liquor in the joined together at right angles, whereof that which barometer. carries the thread and plummet is about a foot and a The Do&or’s fcale for the barometer is ten inches half long ; the thread is hung towards the top of the Jong, and divided into tenths; fo that fuch an infiru- branch, at the point 2. The middle of the branch ment will ferve for any heights not exceeding ten feet, where the thread partes is hollow, fo that it may hang each tenth of an inch anfwering to a foot in height. free every where : but towards the bottom, w here there .The potior made no allowance for the decreafe of is a little blade of filver, whereon is drawn a line perdenfity in the air, becaufe he did not propofe this ma- pendieular to the telefcope, the faid cavity is covered chine for meafuring mountains (though, writh a proper by two pieces of brafs, making as it were a kind of allowance for the decreafing denfity of the air, it will cafe, lefi the wind rtiould agitate the thread; for which, 11 fco very well), but for heights that want U> ]?e iyiowjt ttap UicJihcr bl&ds is covered with a glafis 0, to the

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