Among Lockyer's other works are - The Dawn of Astronomy (1894), to which Stonehenge and other British Stone Monuments astronomically considered (1906) may be considered a sequel; Recent and coming Eclipses (1897); and Inorganic Evolution (1900).
The only phenomena of the sort available are eclipses of Jupiter's satellites, especially of the first.
It is remarkable that no records of eclipses are known from Egyptian documents.
It is remarkable that the discussion of ancient eclipses of the moon, and their comparison with modern observations, show only a small and rather doubtful change, amounting perhaps to less than one-hundredth of a second per century.
The notions of the penumbra and umbra are important in considering eclipses (q.v.).
Chrystal's Algebra, where also may be found details of the application of continued fractions to such interesting and important problems as the recurrence of eclipses and the rectification of the calendar.
The equation of light is the time taken by light to traverse the sun's mean distance from the earth; it can be found by the acceleration or retardation of the eclipses of Jupiter's satellites according as Jupiter is approaching opposition or conjunction with the sun; a recent analysis shows that its value is 498.6", which leads to the same value of the parallax as above, but the internal discrepancies of the material put its authority upon a much lower level.
He mentioned four: (1) by a watch to keep time exactly, (2) by the eclipses of Jupiter's satellites, (3) by the place of the moon, (4) by a new method proposed by Mr Ditton.
Opening with a vision of Eve in Paradise which eclipses Milton's in beauty no less than in sublimity - a dream of the mother of mankind at the hour when she knew the first sense of dawning motherhood, it closes with a vision of the trumpet to be sounded on the day of judgment which transcends the imagination of Dante by right of a realized idea which was utterly impossible of conception to a believer in Dante's creed: the idea of real and final equity; the concept of absolute and abstract righteousness.
It was undertaken with the simple design of furnishing a preface to his younger son's translation of Shakespeare; a monument of perfect scholarship, of indefatigable devotion, and of literary genius, which eclipses even Urquhart's Rabelais - its only possible competitor; and to which the translator's father prefixed a brief and admirable note of introduction in the year after the publication of the volume which had grown under his hand into the bulk and the magnificence of an epic poem in prose.
After the days of Khammurabi, the cult of Marduk eclipses that of Bel (q.v.), and although during the five centuries of Cassite control in Babylonia (c.1750-1200B.C.), Nippur and the cult of the older Bel enjoy a period of renaissance, when the reaction ensued it marked the definite and permanent triumph of Marduk over Bel until the end of the Babylonian empire.
They copied the Ba by Ionian asterisms, appropriated Babylonian knowledge of the planets and their courses, and learned to predict eclipses by means of the " Saros."
In the Ephemerides published year by year, the times of new moon were given, together with the calculated intervals to the first visibility of the crescent, from which the beginning of each month was reckoned; the dates and circumstances of solar and lunar eclipses were predicted; and due information was supplied as to the forthcoming heliacal risings and settings, conjunctions and oppositions of the planets.
He compiled the Hakimite Tables of the planets, and observed at Cairo, in 977 and 978, two solar eclipses which, as being the first recorded with scientific accuracy, 4 were made available in fixing the amount of lunar acceleration.
Romer, on the other hand, deserves full credit for originating the transit-circle and the prime vertical instrument; and he earned undying fame by his discovery of the finite velocity of light, made at Paris in 1675 by comparing his observations of the eclipses of Jupiter's satellites at the conjunctions and oppositions of the planet.
Assuming the mean motion of the moon to be known and the perigee to be fixed, three eclipses, observed in different points of the orbit, would give as many true longitudes of the moon, which longitudes could be employed to determine three unknown quantities - the mean longitude at a given epoch, the eccentricity, and the position of the perigee.
By taking three eclipses separated at short intervals, both the mean motion and the motion of the perigee would be known beforehand, from other data, with sufficient accuracy to reduce all the observations to the same epoch, and thus to leave only the three elements already mentioned unknown.
The same three elements being again determined from a second triplet of eclipses at as remote an epoch as possible, the difference in the 1 A.
The value of the equation of centre derived from eclipses is thus 6.29° sin g - I.
But Edmund Halley found, by a comparison of ancient eclipses with modern observations, that the mean motion had been accelerated.
This value was found by himself and Airy to represent fairly well several ancient eclipses of the sun, notably the supposed one of Thales.
It was therefore surprising when, in 1877, Simon Newcomb found, by a study of the lunar eclipses handed down by Ptolemy and those observed by the Arabians - data much more reliable than the vague accounts of ancient solar eclipses - that the actual apparent acceleration was only about 8.3".
12.19 Hansen's revised, but still theoretically erroneous, result is 12.56 The value which best represents the supposed eclipses (1) of Thales, (2) at Larissa, (3) at Stikkelstad is about 111 The result from purely astronomical observation is 8.3 Inequalities of Long Period.
It has already been shown that such creatures, thunder-birds, snakes, dragons, and what not, people the sky in the imagination of Zulus, Red Men, Chinese, Peruvians, and all the races who believe that beasts hunt the sun and moon and cause eclipses.'
Within two years of their first discovery, he had constructed approximately accurate tables of the revolutions of Jupiter's satellites, and he proposed their frequent eclipses as a means of determining longitudes, not only on land, but at sea.
He attempted, not without success, to give a scientific account of eclipses, meteors, rainbows and the sun, which he described as a mass of blazing metal, larger than the Peloponnesus; the heavenly bodies were masses of stone torn from the earth and ignited by rapid rotation.
For long ages astronomy and astrology (which might be called astromancy, on the same principle as "chiromancy") were identified; and a distinction is made between "natural astrology," which predicts the motions of the heavenly bodies, eclipses, &c., and "judicial astrology," which studies the influence of the stars on human destiny.
From certain expressions used in astrological texts that are earlier than the 7th century B.C. it would appear, indeed, that the beginnings at least of the calculation of sun and moon eclipses belong to the earlier period, but here, too, the chief work accomplished was after 400 B.e., and the defectiveness of early Babylonian astronomy may be gathered from the fact that as late as the 6th century B.C. an error of almost an entire month was made by the Babylonian astronomers in the attempt to determine through calculation the beginning of a certain year.
Eight British government expeditions for observing total solar eclipses were conducted by him between 1870 and 1905.
Firdousi accepted the challenge, and the three poets having previously agreed upon three rhyming words to which a fourth could not be found in the Persian language, 'Ansari began "Thy beauty eclipses the light of the sun"; Farrakhi added "The rose with thy cheek would comparison shun"; 'Asjadi continued "Thy glances pierce through the mailed warrior's johsun"; 1 and Firdousi, without a moment's hesitation, completed the quatrain "Like the lance of fierce Giv in his fight with Poshun."
A few latitudes had indeed been observed, but although Hipparchus had shown how longitudes could be determined by the observation of eclipses, this method was in reality not available for want of trustworthy time-keepers.
Ptolemy knew but of a few latitudes which had been determined by actual observation, while of three longitudes resulting from simultaneous observation of eclipses he unfortunately accepted the least satisfactory, namely, that which placed Arbela 45° to the east of Carthage, while the actual meridian distance only amounts to 34°.
Unfortunately these eclipses are not sudden but slowly changing phenomena, so that they cannot be observed without an error of at least several seconds, and not infrequently important fractions of a minute.
The zodiac was a Babylonian invention of great antiquity; and eclipses of the sun as well as of the moon could be foretold.
- The invention of this instrument has generally been ascribed, as in the ninth edition of this work, to the famous Neapolitan savant of the 16th century, Giovanni Battista della Porta, but as a matter of fact the principle of the simple camera obscura, or darkened chamber with a small aperture in a window or shutter, was well known and in practical use for observing eclipses long before his time.
It is believed to have been in use from the very time of its origin; for the observations of eclipses which were collected in Chaldaea by Callisthenes, the general of Alexander, and transmitted by him to Aristotle, were for the greater part referred to the beginning of the reign of Nabonassar, founder of the kingdom of the Babylonians.
John Goodricke established in 1782 the periodicity of its change in about 2 d 21 h, and suggested their cause in recurring eclipses by a large dark satellite.
The period of Algol, as measured by its eclipses, is subject to complex irregularities.
The alternate delay and acceleration of the eclipses are then merely apparent; they represent the changes in the length of the light-journey as the stars perform their wide circuit.
Inequalities of the required sort in the returns of the eclipses would ensue; moreover, their duration should concomitantly vary with the varying distance from periastron at the times of their occurrence.
I purpose to discourse with him concerning eclipses, for what is there which we may not hope for at his hands," and he also states " that he was wholly taken up and employed about the noble invention of logarithms lately discovered."
It contains an easy and accurate method for calculating eclipses; an essay on colour, in which three primary colours are recognized; a catalogue of 998 zodiacal stars; and a memoir, the earliest of any real value, on the proper motion of eighty stars, originally communicated to the Gottingen Royal Society in 1760.
On the Eclipses of Agathocles, Thales, and Xerxes," Phil.
Further, we know that in the 8th century B.C., there were observatories in most of the large cities in the valley of the Euphrates, and that professional astronomers regularly took observations of the heavens, copies of which were sent to the king of Assyria; and from a cuneiform inscription found in the palace of Sennacherib at Nineveh, the text of which is given by George Smith,5 we learn that at that time the epochs of eclipses of both sun and moon were predicted as possible - probably by means of the cycle of 223 lunations or Chaldaean Saros - and that observations were made accordingly.
25), and a great dragon or serpent is often the cause of eclipses, so that in India, on the occasion of an eclipse, its attention can be attracted by bathing in a sacred stream, or by a ritual which includes the worship of the image of the snake-god (i.
The generally recognized principal Avatars do not, however, by any means constitute the only occasions of a direct intercession of the deity in worldly affairs, but - in the same way as to this day the eclipses of the sun and moon are ascribed by the ordinary Hindu to these luminaries being temporarily swallowed by the dragon Rahu (or Graha, " the seizer") - so any uncommon occurrence would be apt to be set down as a special manifestation of divine power; and any man credited with exceptional merit or achievement, or even remarkable for some strange incident connected with his life or death, might ultimately come to be looked upon as a veritable incarnation of the deity, capable of influencing the destinies of man, and might become an object of local adoration or superstitious awe and propitiatory rites to multitudes of people.
In his investigation he employed the eclipses of the moon recorded in the Almagest, the Arabian eclipses between A.D.
800 and 1004, extracted from Caussin's translation of Ibn Junis, the eclipses and occultations of Bullialdus, Gassendi, and Hevelius, of the French astronomers at Paris and St Petersburg, and of Flamsteed at Greenwich, and deduced a secular acceleration of 8.8", agreeing well with the theoretical value.
Among these are papers on The Recurrence of Solar Eclipses, A Transformation of Hansen's Lunar Theory, Development of the Perturbative Function and its Derivatives.
C. Manitius, Leipzig, 190 9); H€pi v4aipas (De sphaera); Hap6.4paats EisTi 7 v IIToXEµalov TETpit 3L(3Xov, a paraphrase of the difficult passages in Ptolemy's astrological work Tetrabiblus; Els TO 7rpWTOV Ei cXelbov UTot X ELWv, a commentary on the first book of Euclid's Elements; a short treatise on the effect of eclipses (De effectibus eclipsium, only in a Latin translation).
But that native land was too far off, and for a man going a thousand miles it is absolutely necessary to set aside his final goal and to say to himself: "Today I shall get to a place twenty-five miles off where I shall rest and spend the night," and during the first day's journey that resting place eclipses his ultimate goal and attracts all his hopes and desires.