Page:Cyclopaedia, Chambers - Volume 2.djvu/231

 MOR

( &i )

MOR

him. In this Situation /he is call'd by the Greek: Fhof- fhoms; by the Launs L«cfer,{£c. See Phosphorus. Morning Tmtigkt, fee Crepusculum. MORPHEW, is that Freckle or Scurf which breaks out fometimes upon the Skin, particularly about the Forehead. See Freckles.

MORSELLI, andMoRsun, antient Names for thole Forms of Medicines which were to be chew'd in the Mouth, as a Lozenge j the Word fignifying a little Mouth- ful. See Lozenge.

MORSUS Dialxti, Devil's Bit ; a Plant which feems to have a fringe around its Leaves, is thus call'd.

From a likenefs hereto, has the Edge or Sel'idge of the TuU Fallopian*, obtain'd the fame Appellation. See Fallopian.

MORSUS Canis raildi, > s C Hydrophobia. MORSUS nper.t, S I Viper.

MORT d'slncejlre, in Law, fee Assize of Mori d An- eefire. ..

MORTALITY, a Term frequently ufed to fignify a contagious Difeafe, which dcllroys great Numbers either of Men, or Beads.

Bills of Mortality, are Weekly Lifls compiled by the Parifh Clerks inandabout London, containing the Numbers of fuch asdic of each Difeafe, aswellasof thofe that are born every Week.

The Bills are of fome (landing in England, in imitation wheteof they are now eflabliJhcd at Paris, .They are very ufeful on feveral accounts, particularly in judging of the 'Mortality of any Difeafe, and whether an Epidemic or In- fectious Diitemper increafes or abates.

Mr. Gruimt, who examin'd thofe of London very accu- rately, has wrote an exprefs Treatife of 'em. Among other things, he calculates from 'em, that of 100 Perfons who are born in the fame Week, there are but 04 left at the end of fix Years ; but 40 at the end of fixteen Years ; at the end of twenty fix 1 ears, but 2.5; and rhe end of thirty fix Years, but 16 ; at the end of forty fix Years, but 10 ; at the end o r fifty fix, no more than fix ; at the end of fixty fix Years, but 5 ; ar the enJ of feventy fix, but 1 ; and at the end of eighty Years, they are reduced to none.

He likewife makes it appear, that in England in general, more are born than die ; but in London, more die than are born : The Proportion of Births to Purials, in the former, being as 1 ^ to one ; in the latter as T V to one. Thus aifo Ciiies and Market-Towns are found to bury i. T | r tp I Birth. But in Paris they outdo London ; their deaths being li to 1 Birth. In the Villages of England, fewer die than ate born ; there being but one death to 1. ^ 7 5 Births. See Marriag E.

MORTAR, or Morter, in Architecture, is a Prepa- tionof Lime,Sand, iSc. mixedup with Water ; ferving, as it Cement, to bind the Stones, IS'- of a Building. See Building, Cement, £fJc.

TheAntients had a kind of Mortar fo very hard and binding, that, after fo long a Duration, 'tis next to im- poffibleto feparate the Parts of fome of their Buildings ; tho' there are fome who afcribe that excelTive Strength to Time, and the Influences of certain Properties in the Air, which is found to harden fome Bodies very furprizingly.

De Lorme obferves, that the bell Morr«r is that made of Tuzzuoli ; adding, that Ft penetrates black Flints, and turns 'em white.

The Lime ufed in the antient Mortar is faid to be burnt from the hardeft Stones, and even Fragments of Marble. See Lime.

Mr. Worledge obferves, that fine Dull makes weak Mortar ; and the rounder the Sand, the ffronger the Mortar. He therefore advifes the Sand to be wafhed e'er mixed ; and adds, that dirty Water weakens the Mortar considerably. See Sand.

The Proportion of Lime and Sand in our common Mor- tar is extremely variable. Vitruvius prefcribes three patts of Pit-Sand and two of River-Sand to one of Lime; but the Sand here feems to be over-dofed. About London, the Proportion of Sand to quitk Lime is as 36" to 25. In fome Parts they ufe equal Quantities of each.

Wolf its obferves, that the Sand fhould be dry and (harp, fo as to prick the Hands when rubbed ; yet not earthy, fo as to foul the Water it is wafh'd in.

Vitruvius obferves, that Folfil-Sands dry fuoner than thofe taken out of Rivers. Whence, he adds, the latter is fittefl for the Infides, the former for the Outfides of a Building. He Subjoins, that Foffil-Sand lying long in the Air, becomes earthy. Palladia takes notice, that of all Sands white ones are rhe worll ; the teafon is owing to their want of Afperity.

Mixing and tteirfmgo/ Mortar ; M. Felibien obferves that the Antient Mafonswere fo very fcrupulous herein, that the Greeks kept ten Men confiantly employ 'd for a long fpace of time, to each Bafon, which

.ender'dit of fuch prodigious Hardnefs, that I'iimvius ielU us the Pieces of Plaifter falling off from old Walls ferved to make Tables. Felibien adds, it is a Maxim among old Mafons to their Labourers, that they fhould dilute with the Sweat of their Brow, i.e. labour it a long time, inftead of drowning it with Water, to have done the fooner. ■ Befides the common Mortar ufed in laying of Stones, Bricks, i$c. there are feveral other kinds. As,

White Mortar, ufed in Plaiflering the Walls and Ceilings ; made of Ox-Hair mixed with Lime and Water, without any Sand. SeePLAisTER.

The Mortar ufed in making of Water-Courfes,Cifierns, cjfe. is very hard and durable, made of Lime and Hog's- Greafe, fometimes mix'd with the Juice of Figs, and fometimes with liquid Pitch : after Application it is wafhed over with Linfeed-Oil. See Cistern.

Mortar for Furnaces, iS'c. is made wirh red Clay wrought in Water, wherein Horfe-Dung and Chimney-Soct has been fieep'd. See Furnace.

Mortar for Sim-Dials on Walls may be made of Lime and Sand temper'd with Linfeed Oil ; or, for want of that, with fcumm'd Milk. This will grow to the Hard- nefs of a Stone.

In Buildings, one part of wafh'd Soap- Allies mixed with another of Lime and Sand, make a very durable Mortar.

MORTAR, or Mortier, a Badge, or Enfign of Dig- nity bore by the Chancellors, and Great Preiidentsof the Parliaments of France.

It confilts of a Piece of Velvet edged with a Gold-Lace, They formerly bore it on their Head, but now in their Hands.

Hence they are call'd Prefidents a Mortier. MORTAR-PIECE, a Ihort Piece of Ordnance, very thick and wide, proper for the Carriage of Bombs, Car- caffes, Shells, 'Stones, Sic. Scc-Ordnance, Bomb, Car- cass, c5c.

There are two kinds of Mortars ; the one hung, or mount- ed on a Carriage with low Wheels, after the manner of Guns, call'd Pendent or Hanging Mortars : The other fixed on an immoveable Bafe, call'd Standing Mortars.

At the head of the Bore, orChafe of ;ne Mortar, is the Chamber, for the Charge of Powder. This is ufually made Cylindrical, all but the Bafe, which they make Hemi- fphcrical : Tho' fome of the later Engineers prefer Sphe 1 rical Chambers ; as the Surface of thofe being lefs, under equal Capacities, make lefs Refiftance to the Gun-Powder.

SeeCHAMBER.

The Thicknefs of the Mortar about the Chamber is to be much greater than about the Chafe 5 by reafon the Gun-Powder makes a much greater Effort about the Chamber than elfewhere. The Diameter of the Chamber to be much lefs than that of the Bore ; by reafon Bombs, Shells, &c. are much lighter than Bullets of equal Dia- meters ; and, confequently, lefs Powder fufEces. See Bullet.

To charge, or load a Mortar, the proper Quantity of Gun Powder is put into the Chamber; and if there be any vacant fpace, they fill it up with Hay ; fome chufe a wooden Plug. Over this they lay a Turf ; fomea wooden Tampian fitted to the Bore of the Piece ; and laflly the Bomb, taking care that the Fufee be in the Axis thereof, and the Orifice be turn'd from the Muzzle of the Piece. What remains, is to be fill'd up with Hay, Straw, Turf, ££?c- fo as the Load may not be exploded without the utmoft Violence. See Charge.

The Quantity of Gun-Powder to be ufed, is found by dividing the Weight of the Bomb by ;o. Tho' this Rule is not always to be ffrictly obferved. See Gun-Powder.

To elevate the Mortar, fo as its Axis may make any given Angle with the Horizon ; they apply the Artillery- Level, or Gunner's Quadrant 5 the ufe whereof fee under the Articles Level and Quadrant.

An Elevation of -o or ho Degrees is what it commonly chofefor rendring MortarsmcA ferviceable in calling Shells into Towns, Forts, &c, tho' the greater! Range be at 45^. See Range.

If all Mortar- Pieces were, as they ought to be, exactly Similar, and their Requifitesof Powderas the Cubes of the Diameters of their feveral Bores; and it their Shells, Bombs, Carcaffes, cift". were alfo Similar, then, compa- ring like with like, their Ranges on the Plane of the Ho- rizon, under the fame Degree of Elevation, would be equal ; and, confequently r one Piece being well proved, /. e. the Range of the Granado, Bomb, Carcafs, ej?c. be- ing found to any Degree of Elevation, the whole Work of the Mortar- Piece would become very eafy, and exact.

But fince Mortars are not thus Similar, 'tis required that the Range of the Piece at fome known Degree of Eleva- tion be accurately found by meafuring ; and from hence all the other Ranges may be determined.

Thus, to find the Range of the Piece at any other Eleva- tion required ; fay, as the Sine of double the Angle under

which