Astronomy Explained Upon Sir Isaac Newton's Principles And made easy to those who have not studied mathematics

This book uses a number of astronomical symbols, including signs of the Zodiac (♈, ♉, ♊, ♋, ♌, ♍, ♎, ♏, ♐, ♑, ♒, ♓), symbols for planets (☿, ♀, ⊕, ♂, ♃, ♄) and for the sun and m...

23. This Planet appears to us with all the various phases of the Moon, when viewed at different times by a good telescope; save only that he never appears quite Full, because hi...

58. The Moon has no such Atmosphere, or body of air surrounding her as we have: for if she had, we could never see her edge so well defined as it appears; but there would be a s...

86. Every person who looks upon, and compares the Systems of Moons together, which belong to Jupiter and Saturn, must be amazed at the vast magnitude of these two Planets, and t...

106. Gravity also, like all other virtues or emanations issuing from a centre, decreases as the square of the distance increases: that is, a body at twice the distance attracts...

125. The Earth’s bulk is but a point, as that at _C_, compared to the Heavens; and therefore every inhabitant upon it, let him be where he will, as at _n_, _e_, _m_, _s_, &c. se...

140. The _Ptolemean System_ § 96, which asserts the Earth to be at rest in the Center of the Universe, and all the Planets with the Sun and Stars to move round it, is evidently...

159. The celebrated ARCHIMEDES affirmed he could move the Earth if he had a place to stand on to manage his machinery[32]. This assertion is true in Theory, but, upon examinatio...

177. According to [42]Dr. KEILL, and other astronomical writers, it is entirely owing to the Atmosphere that the Heavens appear bright in the day-time. For, without an Atmospher...

195. These last numbers shew, that although we have the relative distances of the Planets from the Sun to the greatest nicety, yet the best observers have not hitherto been able...

Let _S_ be the Sun, _ABCDEFGH_ Saturn’s Orbit, and _IKLMNO_ the Earth’s Orbit. Both Saturn and the Earth move according to the order of the letters, and when Saturn is at _A_ hi...

221. The fixed Stars appear to go round the Earth in 23 hours 56 minutes 4 seconds, and the Sun in 24 hours: so that the Stars gain three minutes 56 seconds upon the Sun every d...

230. This part of the Equation of time may perhaps be somewhat difficult to understand by a Figure, because both halves of the Ecliptic seem to be on the same side of the Globe;...

+------------------------------------------------------------------+ | _A_ TABLE _shewing the Precession of the Equinoctial | | Points in the Heavens, both in Motion and Time; |...

+------------------------------------++--------------++------------------------+ | Sidereal Years. || Julian Years.|| Solar Years. | +-------+---------+----+----+--------++-----...

+-----------------------------------------------------------------------------------------+ | A TABLE of the Equation of natural Days, shewing what Time it ought to | | be by th...

_The Moon’s surface mountainous: Her Phases described: Her path, and the paths of Jupiter’s Moons delineated: The proportions of the Diameters of their Orbits, and those of Satu...

268. The Moon’s path being concave to the Sun throughout, demonstrates that her gravity towards the Sun, at her conjunction, exceeds her gravity towards the Earth. And if we con...

279. Having rectified the Globe, turn it until the patch at _0_, about the beginning of ♓ Pisces on the half _LUI_ of the Ecliptic, comes to the Eastern side of the Horizon; and...

295. The cause of the Tides was discovered by KEPLER, who, in his _Introduction to the Physics of the Heavens_, thus explains it: “The Orb of the attracting power, which is in t...

313. When the Sun’s light is so intercepted by the Moon, that to any place of the Earth the Sun appears partly or wholly covered, he is said to undergo an Eclipse; though proper...

“324. For a farther illustration, THUCYDIDES relates, that a solar Eclipse happened on a Summer’s day in the afternoon, in the first year of the _Peloponnesian_ war, so great th...

+------+--------------------+-----+----------+---------+----------+ | Bef. | Eclipses of the Sun| | M. & D. | Middle | Digits | | Chr. | and Moon seen at | | | H. M. | eclipsed...

+------+-----+----------+----------+----------+ | Aft. | | M. & D. | Middle | Digits | | Chr. | | | H. M. | eclipsed | +------+-----+----------+----------+----------+ | 1486 | �...

The Eclipses from STRUYK were observed: those from RICCIOLUS calculated: the following from _L’Art de verifier les Dates_, are only those which are visible in _Europe_ for the p...

339. Thus it appears, that from the vernal equinox to the autumnal, the North Pole is enlightened; and the Equator and all its parallels appear Semi-ellipses as seen from the Su...

+------------------------------------+----------+-------------+-------------+ | | | Sun’s Anom. | Moon’s Ano. | | | D. H. M. +-------------+-------------+ | | | s ° ʹ | s ° ʹ |...

359. PRECEPT I. We are to consider, that the beginning of Aries and of Libra, which are the Equinoctial Points, are equidistant from the beginning of Cancer and of Capricorn, wh...

381. Apply one side of a Square to the Line of the Moon’s Path, and move the Square backward or forward until the other side cuts the same hour and minute both in the Path of th...

+-------------------------------------------------------------------------+ | TABLE I. _The mean time of New Moon in_ March, _the mean Anomaly of the | | Sun and Moon, the Sun’s...

The first, second, third, and fourth Tables may be continued, by means of the sixth, to any length of time: for, by adding 12 Lunations to the mean time of the New or Full Moon...

+----------------------------------------------------+ | TABLE VII. _The number of Days, reckoned | | from the beginning of_ March, _answering to | | the Days of all the mean Ne...

391. The Stars are said to be fixed, because they have been generally observed to keep at the same distance from each other: their apparent diurnal revolutions being caused sole...

410. The time measured by twelve Revolutions of the Moon, from the Sun to the Sun again, is called the _Lunar Year_; it contains 354 days 8 hours 48 minutes 37 seconds; and is t...

If 11 days be added to the time of any New Moon in this Table, it will give the time thereof according to the _New Style_ till the year 1800. And if 14 days 18 hours 22 minutes...

431. The _Dionysian_ or vulgar Æra of _Christ_’s birth was about the end of the year of the _Julian_ Period 4713; and consequently the first year of his age, according to that a...

+-------------------+------------------------------------------------+ | After Christ | Hundreds of Years. | +-------------------+------+------+------+------+------+------+-----...

The great flat Ring supported by twelve pillars, and on which the twelve Signs with their respective Degrees are laid down, is the Ecliptic; nearly in the center of it is the Su...

439. The _Planetary Globe_. In this Machine, _T_ is a terrestrial Globe fixed on its Axis standing upright on the Pedestal _CDE_, on which is an Hour Circle, having its Index fi...

_Astronomy_, the great advantages arising from it both in our religious and civil concerns, 1 Discovers the laws by which the Planets move, and are retained in their Orbits, 2 _...

If a thread be tied loosely round two pins stuck in a table, and moderately stretched by the point of a black lead pencil carried round by an even motion and light pressure of t...

M. _Maupertuis_, in his dissertation on the figures of the Celestial Bodies (p. 61-63) is of opinion that some Stars, by their prodigious quick rotations on their Axes, may not...