Solution. By an artificial Day is here meant from Sun rifing to Sun fetting, and beyond the Tropics and nearer the Poles the Days are encreafed when the Sun comes on that fide the Equator, from twenty four Hours to about a hundred Days long; fo that there would not be a neceffity of travelling above four Miles every twelve Hours; to compleat the Terms of the Paradox.

Paradox 41. There are three distinct places on the Continent of Europe, lying under the fame Meridian, and at fuch a Distance that the Latitude of the third, furpaffeth that of the fecond, fo many Degrees and Minutes exactly, as the fecond furpaffeth the firft, and yet the true Distance of the first and third from the fecond, or intermediate place, is not the fame by a great many

Miles.

Solution. The Figure of the Earth being not exactly round, as is generally conceived, but what it termed by Geometricians an oblate Spheroid, which is the Shape of a Bowl, fo that the Axis is shorter than the Diameter, confequently will caufe fuch a Difference as expreffed in the Paradox.

Paradox 42. There are two diftinct places on the Continent of Europe, fo fituated in respect of one another, that tho' the first doth lie Eaft from the fecond, yet the second is not West from the first.

Solution. If the artificial Globe is placed in an oblique Pofition, then it will appear, tho' two places bear due Eaft and Weft from one another, yet measured by the Quadrant of Altitude, they will not answer to the true bearing as they are on the natural Globe.

Paradox 43. There is a certain European Island, the Northermoft Part whereof doth frequently alter both it's Longitude and Latitude.

Solution. There are floating Iflands in feveral Parts of the World, and whenever they are moved

from

from one Place to another, not only the northern, but every Part alters in Longitude and Latitude.

Paradox 44. There is a certain place in the Island of Great Britain, where the Stars are always vifible at any time of the Day if the Horizon be not overcast.

Solution. In a deep Well or Coal-pit the furrounding Light which the Atmosphere spreads in the open Air, does not prefs on the Sight; fo that if the Shaft of the Well or Pit be strait, and there be Stars in or near the Zenith after stedfastly looking up a Minute or two, you'll difcover them; hence feveral Aftronomers have had Wells for that purpose.

Paradox 45. It may be clearly demonstrated by the Terreftial Globe that it is not above twenty four Hours failing from the River of Thames in England, to the City of Messina in Sicily, at a certain time of the Year, provided there be a brisk North Wind, a light Frigate, and an Azimuth Compass. Solution. This is meant of the Artificial Globe, and Hour-Index.

С НА Р.

CHA P. XXXV.

Of the three Parts of the Art of Navigation; and firft of the Structure of a Ship.

PROPOSITION I.

The Art of Navigation teaches how a Ship may be commodiously and fafely brought from one Place to another, thro' the Sea, by the Help of the Wind.

A

ND because the Situation of one Place with another is confidered in this Part; this Do&trine is juftly brought in here in the Comparative, or Relative, Part of Geography.

AND I think in this Art (that is fo noble and useful to human Society) there are properly three Parts; 1. Of the Structure of a Ship; to which may be referred the Ship's Motion in the Water. 2. Of the Burden to be carried in the Ship. 3. The governing of the Ship, which is called, in general, the Art of Navigation, by way of Excellency; and is the chief Part thereof; the other two belonging principally to Mechanics and Statics; whereas the directing of the Ship depends wholly upon Geography.

PRO

PROPOSITION II.

In building a Ship these things are to be confidered.

1. THE Choice of the Wood or Matter that will last longeft in the Sea; for which fee Vitruvius, and other Authors: and here alfo is to be confidered how the Wood is to be prepared, it's Denfity increased, and the ufelefs Moisture taken away by Fire; and alfo defended from Corruption by covering with Pitch, &c. which natural Philofophy teaches.

2. THAT fuch a Figure be given to the Ship which is fittest for Motion in the Sea, and requires the least Force to move it. To this belongs the different Shapes of the antient and modern Ships, wherein several things worthy to be known may be produced from Antiquity and modern. Inventions; and feveral things propofed from Statics and Phoronomics, concerning the Motion of Bodies of different Figures; efpecially what the divine Archimedes hath left us of the Motion of Bodies in Water: but feeing few delight in fuch things, and our Design is only to give a Compendium of general Geography, I thought fit to omit the Explication of these things, and to enumerate only the Heads and Parts of that Doctrine: which I fhall alfo do in what follows. And if we fhall understand that these things are acceptable to Youth, we shall add them in another Edition, fully explained; and other things likewife, to the preceding Chapters.

BUT to return; a good Shape is a great Matter for moving easily and fwiftly in the Water; and for this chiefly are Ships commended, especially in Sea-Fights: and there is a great Difference found among Ships in this particular VOL. II,

Τ

but

but this depends on Statics, and the Laws of Motion.

3. IN the Structure of a Ship, it's Figure is to be fuch as that it may be easily defended against Storms and Waves, that it may not be overfet but of this more in the fecond Part, of the Ship's Burden. This alfo belongs to Statics, and the Motion of Fluids, as Air or Water.

4. THE bignefs of a Ship is to be confidered ; where feveral things may be advanced by comparing Antiquity with the prefent Time. The Ship Alexandrina, made by the Command of Hiero, King of Sicily, and fent as a Prefent to Ptolemy, King of Egypt, Archimedes being the Builder, was thought to be twelve thoufand Tun; and Callixenus writes, that Philopator's Ship was two hundred eighty Cubits long, thirty eight broad, and forty eight high. The biggest ships at prefent are thofe of the Spaniards and Portuguese, which they call Caracs, which carry One thoufand and more Vehes or Lafts, as the Germans call them; each being twelve Tun. The Dutch Ships do not carry above feven hundred Lafts (f).

5. THERE belongs chiefly to the Structure of a Ship, the Knowledge of the building of the Keel, the Rudder, the Ribs, the Stern, and Fore-part, the Mafts, the Sails, the Cables, the Anchors; of which not only the Matter, Figure, and Confistency, but alfo their Bulk and Weight is to be confidered.

(f) Here seems to be fome confiderable Miftake about the Burden of Ships; for by Dolia, or Tuns, the Author exprefsly declares, that the means twenty hundred Weight. See

2

Chap. xxxiv. Prop. 1. But the largest Ships of Burden in England and Holland feldom exceed fix or seven hundred Tun. See alfo Prop, 8. of the next Chap

ter.

6. TO