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THE Grecian Stadium, or Furlong, is supposed to be 600 of their Feet, which make 625 Roman, or Rbinland, Feet ; their Foot being a little larger than the Roman.
A GERMAN Mile (15 of which Geogra. phers allow to a Degree) contains 22800 Rbinland Feet, and is accounted 4000 Paces, or 32 Furlongs. It is in Proportion to the Rhinland Mile, as 19 to 15.
THE Italian or Roman Mile is 1000 Paces, which is equal to 4000 Rbinland Feet. Note, The Romans used to call their Mile Lapis, because a Stone was erected at the end of every Mile ; espe. cially in Places adjacent to the City.
A GEOMETRICAL Pace is exactly 5 Feet ; and a Faibom 6 Feet ; which is thought by some to have been the Pace of the Grecians.
A CUBIT is supposed to be a Foot and a half.
THE Parasange, or Persian Mile, is thought to be 30 Furlongs, or 3000 Persian Paces.
THE Schenus, or Ægyptian Mile, according to Herodotus, contains 50 Furlongs, tho' only 40 according to Pliny. Perhaps their Length differed in divers Places, or the Furlongs of the Au. thors might be unequal: Or very likely their Books are corrupted. . THE French League is in Proportion to the Rbinlandis Mile, as 19 to 25; and the Spanish League is to the fame Mile, as 19 to 273 : But because in several Parts of France and Spain their League is found to differ, we cannot be well assured of the Length of these Measures.
THE English Mile is in Proportion to the Rbinlandish, as 19 to 55, of as 19 to 60 (r). But
there (r) The least Part of English and well dryed; whereof 3 in Measure is a Barley-Corn, taken Length make an Inch, &c. as out of the middle of the Ear in the following Table. .
A Table there are three sorts of English Miles, whereof 271 of the longest, 50 of the middle Kind, and 60 of the shortest, make a Degree or 19 Dutch Miles.
THE Danish and Swedish Mile is to the Rbinlandis Mile as 19 to 10; tho' in some Places they use the German Mile.
THE Vorest, or Rulan, Mile is as 19 to 80.
THE Turkish League or Mile is said to be equal to the Italian Mile ; of which 6o make a Degree.
THE Arabian League was formerly accounted the twenty fifth Part of a Degree, or 19 Holland Miles: but they now use another of which 56 make a Degree.
A HUNDRED Indian Miles are thought to equal a Degree. Tho' the Indians commonly describe Distances by a Day, or an Hour's Journey. · THE Inhabitants of Cambaya and Guzarat, use a Measure which they call Cosa, of which 30 make a Degree. ...THE Chinese observe three Measures in their Journies, which they call Li, Pu, and Uchan. Li is the Distance at which a Man's loud Voice may be heard on a Plain, in a calm Air ; which is accounted 300 Geometrical Paces. Their Pu contains ļo Li's;
A Table of English Measure.
12 Feet. 108
72 594 198 1623760 7920660 220 132 | 110 180090 163360 152801 1700, 10561 880
so that 20 Pu's make a Degree. And 10 Pu's make an Uchan, or 30000 Paces; which they account a day's Journey.
Note, A Square Rhinland Mile consists of Square Feet, and a Cubic Mile of Cubic Feet. Also a Mile multiplyed into itself makes a Square Mile; and that again by a Mile makes a Cubic Mile. The same is to be understood of a Square and Cubic Foot, i
SECT. II. Containing fome general and absolute Properties of the Earth, in five Chapters.
CHA P. III,
T HE first and noblest Property of the Earth
| (as exceeding the rest in being more useful and necessary) is it's Figure; without the Knowledge of which there can be nothing well understood or demonstrated in this Science; and all the following Propositions almost entirely depend on, or immediately now, from this; which for that Reason ought to be first treated of.
THERE have been, and are to this Day, feveral Opinions about the Figure of the Earth; for the Vulgar that understand not Geography, imagine it to be extended into a vast Plain bounded with a Circular Line; except where Mountains and Vallies interpose.' Of this strange Opinion was Laftantius and others of the Fathers, who strenuously argued that the Earth was extended infinitely down
wards, wards, and established upon several Foundations (a). This they were inclined to think from some Places of Scripture which they either ill understood or wrong interpreted. Heraclitus, that ancient Philofopher, is said to have been of their Opinion: tho' others say, he supposed the Earth to be in the Shape of a Skiff or Canoo, very much hollowed. But what is more strange Francis Patricius (a modern Philofopher of no small Repute in the last Age) ftrenuously endeavoured to prove, that the Earth was horizontally stretched out and plain under Foot. Anaximander is said by Peucerus to have supposed the Earth like a Cylinder ; tho' that is not so probable, because he tried to measure it, and also invented a sort of a Dial at Lacedæmon, upon which the Top of the Gnomon by it's Shadow marked out the Days of the Equinoxes, and Solstices: which thewed him to have been tolerably skilled in Astropomy, considering the Time he lived in. Leucippus also thought the Earth to be in the Shape of a Drum. These with a great many other absurd Opinions, are by Aristotle and others attributed to the Antients: of which see Aristotle Lib. ii. Cap. 13. de Cælo. - 5
BUT the true and undoubted Opinion, which is defended by all Mathematicians, and almost all Philosophers, is, That the Earth is of a globular or spherical Figure (b).
(a) See Lactantius Lib. iii. Honour and Admiration in it; Chap. 24. and Augustin Lib. xvi. that the true Figure of the Chap. 9. De Civit. Dei. They' Earth, which Men have inhathought their Opinion was fa- bited for so many thousand voured by the Pfalmift. Pfal. Years, is but now begun to be xxiv. 2. and cxxxvi. 6. known a few Years ago. For
(6) Among the many excel- that which all Men thought to lent and wonderful Inventions be globular and truly spherical, of the modern Philosophers, is now found to imitate rather this here is not certainly in the an oval Figure, or that of an last Place, nor hath the least Ellipfis revolved about it's lesser
Axis: So that those Diameters dies, is less in Countries apare longeft which come neareft proaching the Equator than in the Equator, and lessen as they Places near either Pole. The become more remote, but the two famous Philosophers News least Diameter of all is the Axis ton and Huygens being excited which joinech the two Poles. by the Novelty of the Thing,
The Thing will perhaps be bet- and seacrhing more narrowly inter understood if it be represen- to the Cause of it, found thereby ted by a Figure.
that the Earth must have some Let a pop (Fig. 4.) be a cir- other Figure than what was cular Section of the Earth made known; and also demonstrated by the Meridian, such as it was that this Diminution of Weight thought to be formerly and p P doth naturally arise from the the Axis or Diameter joining Rotation of the Earth round it's the Poles, and eq the Diameter Axis; which Rotation, accord. of the Equator: then the oval ing to the Laws of circular MoLine Æ PRP, described upon tion, repels all heavy Bodies the Diameters ÆQ and PP, from the Axis of Motion: fo will represent the Section or that this Motion being swifter true Meridian Line, which for under the Equator than in Parts Distinction fake is made here to more remote, the Weight of differ more from a Circle than Bodies must also be much less it really ought to do; but in there than nearer the Poles. truth, the Proportion is as 692 Therefore the Parts of the O to 689. So that the Line C e cean under the Equator being measuring the Altitude of the made lighter, and according to Earth at the Equator, exceeds the Nature of all Fluids, pressed CP the Altitude at the Pole and forced on either side by the 85200 Paris Feet, or about 17 Waters nearer the Poles, they Miles.
must be raised up to a greater This Affair is well worthy to Height, that so they may better be traced to it's Original, and to support and balance the greater be backed by a Demonftration, Weight of the contiguous Wa so far as our Purpose will permit. ters. Which mutual Libration See the History of the Royal A- is demonstrated upon Supporcademy of Sciences by du Hamel. tion of that Inequality of the Pag. 110, 156, 206. Also Hift. Diameters which we mentioned de I Acad. Roy. 1700, 1701. above. The Figure of the Sea
The French made an Experi- being resembled by the Lands ment about forty Years ago, adjacent, which are every where Thewing that a Pendulum (which raised above the Sea, the aforeis a well known Instrument for said Form must be attributed to measuring of Time) vibrates so the whole terraqucous Globe. much the flower, by how much They that would be more fully the nearer it is brought to the informed in this Matter may Equator: that is, the Gravity, consult Newton's Principia Lib. or Celerity of Descent of the iii. Prop. 19. or Huygen's Treas Pendulum, and of all other Bo- tife of the Cause of Gravity.