« AnteriorContinuar »
of the same from that of Q ; which could by no means happen if the Line B P Q was not circular. 3. In like manner all the Stars when they come to the Meridian ABC, have their Distances from the Zeniths of P, Q, B, in the fame Proportion as the Distances Q P, PB, Q B. Moreover when our Mariners fail towards the South, the Stars which before were depressed under the Horizon, and could not be seen, begin to appear,and by degrees are elevated in proportion to their Course. 4. If several Places be observed in the fame Meridian, and the Stars that pass thro' their Zeniths be noted; the Distances of these Places have the same Proportion one to another, as the Distances of the meridional Points, wherein the several vertical Stars make their southing.
ALSO to prove that the Line of Longitude EBFC is circular, and that the Earth rises into a globular Figure, according to that other Dimension, we need but observe that the Sun and Stars rise and set sooner to those that inhabit eastward of us, but later to them that are more to the west ; and also that the Difference of Time is in proportion to the Distances of their Meridians from ours. Thus, if we suppose two Places directly East, the one distant from us 225 Miles, the other 450, twice as much ; we shall find that in this last Place the Sun riseth two Hours sooner, and in the other one Hour sooner than with us. The Argument will be more clear, if it be proposed about the Sun's approaching the Meridians of divers Places; for their Distances in respect of ours are in Proportion to the Time of the Sun's apparent Motion (or an Arch of the Equator intercepted between our Meridian and theirs) as is evident in Eclipses. These Facts agree precisely to the Demonstrations upon the Artificial Globe: which could not happen if the Earth had any other Figure.
so that the Earth is found to have a spherical Form, both in Longitude and Latitude.
BUT since there seems to be a Difficulty in handling the Longitude, all this may be proved by the Latitude only. Fo: it is manifeft, that the Figure of the Earth is spherical, since all the Sections, or Lines of Latitude, are circular; and pass thro' the same Point or Pole. Because any solid Body whatsoever being cut with innumerable Planes, all. passing thro' the same Point; if the Peripheries of these Sections are circular, the Body itself must be spherical: as is known and allowed by all Geometricians.
THERE is another Reason of no less Force, taken from the Shadow of the Earth upon the Face of the Moon in Lunar Eclipses. For since the obfcured Part of the Moon, caused by the conical Shadow of the Earth, seems always to be bounded with a circular Line ; the Earth itself, for that Reason, must needs be spherical (d). Because it is manifest from Optics that a solid Body being every way opposed to the Sun ; if the Shadow be always conical, che Body itself is spherical.
IF these Arguments are not sufficient, we might produce a great many more, from the consideration of the Earth itself, which perfectly prove the Earth's. Rotundity: such as these ;
(d) Tacquet (in his Aftrono- dow proceed from the Earth itmy Lib. iv.) hath demon- self, or the Atmosphere, (tho' strated that the Shadow of the the latter indeed be the Truth) Earth never reaches so far as the the Thing is the same in the Moon; so that the Moon is dark- present Case: for if the Shadow ened not by the Shadow of the of the Atmosphere be circular, Earth, but by that of ii's At- the Shadow of the Earth which mosphere only; which was ob- is enclosed on every Side there. ferved, cho' not so exactly de. bymut be circular too. Wbi. monftrated, by Kepler and Ric- fon's Aftror. Lett. Pag. 2 riolus. But whether the Sha
- 1. FROM Circumnavigation ; for the Europeans have several times set Sail from Europe, and steer'd their Course directly South and West, 'till they came to the Magellanic Sea ; and from thence to the North and West 'till they returned to Europe from the East; and all the Phænomena, which should naturally arise from the Earth's Rotundity, happened to them. Their Method of failing also was founded upon this Hypothesis ; which could never have succeeded so happily if the Earth had been of any other Figure *.
2. WHEN we take our Departure from high Mountains and Towers; first the lower Parts, then those that are higher, and lastly, their Tops are by degrees depressed, as it were, and hid from us : On the other Hand, when we approach towards them, from a Place at a great Distance, first the Top appears, then the middle Part, and lastly, when we come pretty near, the very Foot of the Mountain is discovered. So that this gradual Appearance and Occultation, is such as must necessarily happen from the spherical Figure of the the Earth.
3. IF we measure the Altitude of any Mountain upon this Supposition, that the Earth is globular ; the Practice is always found to justify the Truth of the Theory.
WE might demonftrate many of these Arguments geometrically ; but (because it would be both
* Ferdinando Magellan was Simon Cordes in the Year 1590. the first who failed round the By Oliver Noort, Anno 1598. Earth, in the Year 1519. he By Cornel Scharten, Anno 1615, performed it in 11 24 Days. Sir And by Jacob Heremites, Anno Francis Drake was the next, in' 1623; and all by directing their the Year 1577. and he perform- Course constantly from East to ed it in 1056 Days. The same Weft; and thus returned into was afterwards : done by Sir Europe, having all along obserThomas Cavendish, in the Year ved the Phænomena which ne1586; in the Space of 777 Days.' cessarily arise upon supposing the I was done again by Mynheer Earth a spherical Body.
laborious laborious and difficult to prove this, or that Line circular, from such Principles, &c.) we shall content ourselves with those evident Proofs above delivered: which being collected into one Sum, will sufficiently demonstrate the Earth to be globular. As, first, the celestial Phänomena (viz. The different Elevation of the Pole; the unequal Altitude of the Sun, at the same Instant, in different Countries; the. Earth's Shadow on the Moon; the vast Increase of the longest Day towards the Poles ; the Rising and Setting of the Stars; their perpetual Appearance near the Pole, &c.) do all equally prove the Earth's Rotundity. Also the terrestrial Appearances (viz.". The Art of Navigation; the Appearance and Occultation of Mountains and Towers; the Distances of Places; the Winds and Points of the Compass, &c.) can only be accounted for by this Figure and no other. Also the artificial Globe, which we make to represent the Earth, exhibits all these Things as they really are on the Earth ; which would certainly, in fome Cafes, be different, except this was it's true Representation. The Earth is not of a plane Figure, as is manifest from the aforesaid Arguments ; nor of a hollow Figure; for then the Sun and Stars would appear sooner to the western Inhabitants than to those of the East: But we see the Rising Sun.every Day : illuminates the Vallies, before it Thines upon the back Parts of the opposite Mountains *..
. * Another Argument is follow, that one (too vast a drawn from the commodious • Part) would be drowned; and and equal Distribution of the another too dry. But being Waters in the Earth. . For thus orbicular, the Waters • since, by the Law of Gra- are equally and commodiously
vity, the Waters will pof- distributed here and there ac- . "sess the lowest place; there. cording as the Divine Provi-, • fore, if the Mals of the Earth •dence saw most fit. Derbam's' • was cubic, prismatic, or any • Pbysico-Theology, Book 2. Ch. 'ocher angular Figure, it would '1. Art. 2.
appear haft: But Hallies, be
• A spherical Body also is the only one that is similar, or hath all it's Parts alike among themselves; so that they may be mutually applied one to another, For if two equal Parts of a Sphere be considered, the Properties of each are the same; which will not hold in any other Body. Thus în measuring the Earth in different Places; if it be performed by the same Method, it is always found of the fame Magnitude: which doth not a little contribute to the Proof of these Affertions.
ANY impartial Person may easily perceive of how little Weight their Reasons are, who believe the Earth to be of a plane Figure. For which they · argue, 1. Because on a clear Day the Earth seems
to be plane, as well as the Sea, if we look every way round about us (e). 2. If the Surface of it was not plane, it would be more easily moved, and more fubject to fall to pieces; whereas Alat Figures are more firm and stable (f). - 3. The Rising or Setting Sun and Moon are cut, as it were, with right Lines; but if the Earth was spherical, they ought to be divided by circular ones. Thus the Ancients reasoned, ridiculousy, as Aristotle tells us. 4. Some argue that the many high Mountains must, of necessity, deface it's Rotundity. 5. Others believe the Sea to be higher than the Earth. 6. Some again think it impossible that Men should stand upon the opposite
(e) This Argument is confu- Power of Attraction upon all ted by what is said above, about the Matter in the Universe, the Appearance and Disappea- whereby all Bodies,' and all rance of Mountains.
the Parts of Bodies, mutually I) A spherical Body is not attract themselves and one ano. fo liable to decay and fracture ther; which, as the Rev. Dr as another, because all the Parts Derham observes, is the natural of the Surface are equidistant Cause of the Sphericity of our from the Center. And we are common Globe. See Newtaught by Sir Isaac Nezoron's ton's Principia, Lib. 3. Prop. Principles, that the Divine Being 7. Also Derham's Pbysico-Theol. at the Creation, beitowed the p. 40. D 4