An almanac is a calendar, in which are set down the rising and setting of the sun, the phases of the moon, the most remarkable positions and phenomena of the heavenly bodies, for every month and day of the year; also the several fasts and feasts to be observed in the church and state, etc, and often much miscellaneous information likely to be useful to the public.
The term is of Arabic origin, but the Arabs were not the first to use almanacs, which indeed existed from remote ages. In England they are known from the fourteenth century, there being several English almanacs of this century existing in manuscript form. They became generally used in Europe within a short time after the invention of printing; and they were very early remarkable, as some are still, for the mixture of truth and falsehood which they contained. Their effects in France were found so mischievous, from the pretended prophecies which they published, that an edict was promulgated by Henry III in 1579 forbidding any predictions to be inserted in them relating to civil affairs, whether those of the state or of private persons.
In the reign of James I of England letters-patent were granted to the two universities and the Stationers' Company for an exclusive right of printing almanacs, but in 1775 this monopoly was abolished. During the English Civil War, and thence onward, English almanacs were conspicuous for the unblushing boldness of their astrological predictions, and their determined perpetuation of popular errors. The most famous English almanac was Poor Robin's Almanac, which was published from 1663 to 1775.
Gradually, however, a better taste began to prevail, and in 1828 the Society for the Diffusion of Useful Knowledge, by publishing the British Almanac, had the merit of taking the lead in the production of an unexceptionable almanac in Great Britain. The example thus set has been almost universally adopted. The circulation of almanacs continued to be much cramped by the very heavy duty of one shilling and threepence per copy until 1834, when this duty was abolished. About 200 new almanacs were started immediately on the repeal.
Almanacs, from their periodical character, and the frequency with which they are referred to, are now more and more used as vehicles for conveying statistical and other useful information, some being intended for the inhabitants of a particular country or district, others for a particular class or party. Some of the almanacs that are regularly published every year are extremely useful, and before the Internet and improved communications were almost indispensable to men engaged in official, mercantile, literary, and professional business. Such in Great Britain were Thorn's Official Directory of the United Kingdom, the British Almanac, Oliver and Boyd's Edinburgh Almanac, and Whitaker's Almanac, now so well known.
In the United States was published The American Almanac, a useful compilation. The Almanach de Gotha, which first appeared at Gotha in 1764, contained in small bulk a wonderful quantity of information regarding the reigning families and governments, the finances, commerce, population, etc, of the different states throughout the world. It was published both in a French and in a German edition. Almanacs that pretend to foretell the weather and occurrences of various kinds are still popular in Britain, France, and elsewhere.
The Nautical Almanack was an important work published annually by the British government, two or three years in advance, in which was contained much useful astronomical matter, more especially the distances of the moon from the sun, and from certain fixed stars, for every three hours of apparent time, adapted to the meridian of the Royal Observatory, Greenwich. By comparing these with the distances carefully observed at sea the mariner could with comparative ease, infer his longitude to a degree of accuracy unattainable in the past by any other way, and sufficient in the past for most nautical purposes. This almanac was commenced in 1767 by Dr. Maskelyne, astronomer royal. The French Connaissance des Temps was published with the same views as the English Nautical Almanac, and nearly on the same plan. It commenced in 1679. Of a similar character was the Astronomisches Jahrbuch formerly published at Berlin. Research Almanac
The Apollo Project was the US space project to land a person on the moon in order to prove to the world the ideological superiority of the American system over that of Communist Russia. It was reportedly achieved by Apollo 11 in July 1969. The three-stage vehicle to carry the astronauts to the moon was code named Saturn, and the contract to develop the Apollo three-man spacecraft was awarded to North American Aviation Incorporated in 1961 by NASA. The first launch into orbit of an Apollo command module was made by Saturn SA-6 on May the 28th 1964, and the first manned flight was made after a fire during ground tests killed the three astronauts - Virgil Grissom, Edward White and Roger Chaffee - on January the 27th 1967.
Controversy surrounds the supposed moon landing, with theories abounding that in 1969 it was technically impossible to land on the moon, and as a result NASA faked the moon landing, filming the 'landing' at the top secret military base, Area 51, in the Nevada desert while the astronauts actually orbited the earth for eight days before returning. This theory was later illustrated in the film 'Capricorn One' which told the fictional story of a faked landing on the planetMars. Research Apollo Project
A clock is an instrument for measuring time and indicating hours, minutes, and usually seconds, by means of hands moving on a dial-plate, and traditionally differing from a watch mainly in having the movement of its machinery regulated by a pendulum, and in not being portable. A clock also chimes, though the term clock is frequently, and incorrectly, applied to the non-chiming instruments for measuring time, which are technically known as a timepiece.
The use of a horologium, or hour-teller, was common even amongst the ancients, but their time-pieces were nothing else than sun-dials, hour-glasses, and clepsydrae. In the earlier half of our era we have accounts of several attempts at clock construction : that of Boethius in the 6th century, the clock sent by Harun al Rashid to Charlemagne in 809, that made by Pacificus, archdeacon of Verona, in the 9th century, and that of PopeSylvester II in the 10th century. It is doubtful, however, if any of these was a wheel-and-weight clock, and it is probably to the monks that we owe the invention of clocks set in motion by wheels and weights. In the 12th century clocks were made use of in the monasteries, which announced the end of every hour by the sound of a bell put in motion by means of wheels. From this time forward the expression, 'the clock has struck,' is often met with. The hand for marking the time is also made mention of.
In the 14th century there are stronger traces of the later system of clock-work. Dante particularly mentions clocks. Richard, abbot of St Albans in England, made a clock in 1326, such as had never been heard of until then. It not only indicated the course of the sun and moon, but also the ebb and flood tide. Large clocks on steeples likewise were first made use of in the 14th century. Watches are a much later invention, although they have likewise been said to have been invented as early as the 14th century. A celebrated clock, the construction of which is well known, was set up in Paris for Charles V in 1379, the maker being Henry de Vick, a German. It probably formed a model on which clocks were constructed for nearly 300 years, and until Huyghens applied the pendulum to clock-work as the regulating power, about 1657. The great advantage of the pendulum prior to the invention of electronic oscillators is that the beats or oscillations of a pendulum all occupy substantially the same time (the time depending on its length), hence its utility in imparting regularity to a time-measurer. The mechanism by which comparative regularity was previously attained, though ingenious and simple, was far less perfect; and the first pendulum escapement that is, the contrivance by which the pendulum was connected with the clock-work, was also less perfect than others subsequently introduced, especially Graham's dead-heat escapement, invented in 1700.
In a watch, prior to the invention of electronics, the balance-wheel and spring served the same purpose as the pendulum, and the honour of being the inventor of the balance-spring was contested between Huyghens and the English pliilosopher Dr. Hooke. Various improvements followed, such as the chronometerescapement, and the addition of a compensation adjustment, by which two metals having unequal rates of expansion and contraction under variations of temperature are combined in the pendulum or the balance-wheel, so that, each metal counteracting the other, the vibrations are isochronous under any change of temperature. This arrangement was perfected by Harrison in 1726, and was especially useful in navigation. Research Clock
A comet is a small body orbiting the sun on an elliptical path with a long tail of dust and ice.
Some comets are only visible by the aid of the telescope, while others can be seen by the naked eye. In the latter case they usually appear like stars accompanied with a train of light, sometimes short and sometimes extending over half the sky, mostly single and more or less curved, but sometimes forked. In a comet which appeared in 1744 the train was divided into several branches, spreading out from the head like a fan. The train is not stationary relatively to the head, but is subject to remarkable movements. The direction in which it points is always opposite to the sun, and as the , comet passes its perihelion the train changes its apparent position with extraordinary velocity. The head of the comet is itself of different degrees of luminosity, there being usually a central core, called the nucleus, of greater brilliancy than the surrounding envelope, called the coma.
Comets were long regarded as supernatural objects, and usually as portents of impending calamity. Tycho Brahe was the first who expressed a rational opinion on the subject, coming to the conclusion that the comet of 1577 was a heavenly body at a greater distance from the earth than that of the moon. The general law of the motion of bodies, as well as his own observations on the comet of 1680, led Isaac Newton to conclude that the orbits of the comets must, like those of the planets, be ellipses, having the sun in one focus, but far more eccentric; and having their aphelions, or greater distances from the sun, far remote in the regions of space.
This idea was taken up by Halley, who collated the observations which had been made of all the twenty-four comets of which notice had been taken previous to 1680. The results were very interesting. With but few exceptions the comets had passed within less than the earth's shortest distance from the sun, some of them within less than one-third of it, and the average about one-half. Out of the number, too, nearly two-thirds had had their motions retrograde, or moved in the opposite direction to the planets. While Halley was engaged on these comparisons and deductions the comet of 1682 made its appearance, and he found that there was a wonderful resemblance between it and three other comets that he found recorded - the comets of 1456, of 1531, and of 1607. The times of the appearance of these comets had been at very nearly regular intervals, the average period being between seventy-five and seventy-six years. Their distances from the sun, when in perihelion, or when nearest to that luminary, had been nearly the same, being nearly six-tenths of that of the earth, and not varying more than one-sixtieth from each other.
The inclination of their orbits to that of the earth had also been nearly the same, between 17 degrees and 18 degrees; and their motions had all been retrograde. Putting these facts together, Halley concluded that the comets of 1456, 1531,1607, and 1682 were reappearances of one and the same comet, which revolved in an elliptic orbit round the sun, performing its circuit in a period varying from a little more than seventy-six years to a little less than seventy-five; or having, as far as the observations had been carried, a variation of about fifteen months in the absolute duration of its year, measured according to that of the earth. For this variation in the time of its revolution Halley accounted upon the supposition that the form of its orbit had been altered by the attraction of the remote planets Jupiter and Saturn as it passed near to them; and thence he concluded that the period of its next appearance would be lengthened, but that it would certainly reappear in 1758 or early in 1759. As the time of its expected reappearance approached, Clairaut calculated that it would be retarded 100 days by the attraction of Saturn, and 518 by that of Jupiter, so that it would not come to the perihelion, or point of its orbit nearest the 500 sun, until the 13th of April, 1759.
It actually reached its perihelion on the 13th of March, 1759, being thirty days earlier than he had calculated. Along with the period of this comet and its perihelion distance, the magnitude and form of its path were also calculated. Estimating the mean distance of the earth from the sun at 95,000,000 miles (the number which was at that time considered as the true one), the mean distance of the comet was calculated to be 1,705,250,000 miles; its greatest distance from the sun, 3,355,400,000; its least distance, 55,100,000; and the transverse or largest diameter of its orbit, 3,410,500,000. This comet, therefore, is a body belonging to the solar system, and quite beyond the attraction of any body which does not belong to that system; and as this is determined of one comet, analogy points it out as being the case with them all. In 1835 it again returned, being first seen at Rome, on August the 5th, and from that time continued to be observed until the end of the year in Europe, and through a great part of spring 1836 in the southern hemisphere.
The comet denominated Encke's comet, which has made repeated appearances, was first observed in 1818, and was identified with a comet observed in 1786, also with a comet discovered in 1795 by Miss Herschel in the constellation Cygnus, and with another seen in 1805. Its orbit is an ellipse of comparatively small dimensions, wholly within the orbit of Jupiter; its period is 1260 days, or about three years and three-tenths. It has been frequently observed since.
Another comet, the history of which is of the utmost importance in the latest theories regarding the connection of these bodies and the periodic showers of shooting-stars, is one known as Biela's comet, discovered in 1826. It revolved about the sun in about 6.75 years, and was identified as the same comet which was observed in 1772 and in 1806. Its returns were noted in 1832, 1839, and 1845. In 1846 it divided into two, returned double in 1852, but has not since been seen, the Supposition being that it has been dissipated, and that it was represented by a great shower of meteors that were seen in November 1872. One of the most remarkable comets of recent times was that known as Donati's, discovered by Dr. Donati of Florence in 1858. It was very brilliant in England in the autumn of that year, and on the 18th of October was near coming into collision with Venus, The year 1881 was remarkable for the number of comets recorded. During that year no fewer than seven comets, including the well-known short-period comet Encke's, were observed. Research Comet
Crescent is a geometrical form resembling the moon in its first quarter, and used as a charge in heraldry. It is perhaps better known as the symbol of the Ottoman Turks and a symbol of Islam. The crescent as an emblem is of very high antiquity, being that of the Greek goddess Artemis or Diana. It is found on medals of many ancient cities, particularly of Byzantium, from whence it is supposed to have been borrowed by the Ottomans. The crescent has given name to a Turkish order of knighthood from the form of the badge, instituted by Selim, sultan of Turkey, in 1801. Research Crescent
Cycle is a term used for every uniformly-returning succession of the same events. On such successions or cycles of years rests all chronology, particularly the calendar. Our common solar year, determined by the periodical return of the sun to the same point in the ecliptic, everybody knows contains fifty-two weeks and one day, and leap-year a day more. Consequently in different years the same day of the year cannot fall upon the same day of the week. And as every fourth year is a leap-year, it will take twenty-eight years (4x7) before the days return to their former order according to the Julian calendar. Such a period is called a solar cycle. The cycle of the moon, or golden number, or Metonic cycle, is a period of nineteen years after which the new and full moons return on the same days of the month. Research Cycle
An eclipse is the interception or obscuration of the light of the sun, moon or other heavenly body by the intervention of another and non-luminous heavenly body. Stars and planets may suffer eclipse, but the principal eclipses are those of the sun and the moon.
An Eclipse of the Moon is an obscuration of the light of the moon occasioned by an interposition of the earth between the sun and the moon; consequently, all eclipses of the moon happen at full moon; for it is only when the moon is on that side of the earth which is turned away from the sun, and directly opposite, that it can come within the earth's shadow. Further, the moon must at that time be in the same plane as the earth's shadow; that is, the plane of the ecliptic in which the latter always moves. But as the moon's orbit makes an angle of more than 5 degrees with the plane of the ecliptic, it frequently happens that though the moon is in opposition it does not come within the shadow of the earth.
An Eclipse of the Sun is an occultation of the whole or part of the face of the sun occasioned by an interposition of the moon between the earth and the sun; thus all eclipses of the sun happen at the time of new moon. As the earth is not always at the same distance from the moon, and as the moon is a comparatively small body, if an eclipse should happen when the earth is so far from the moon that the moon's shadow falls short of the earth, a spectator situated on the earth in a direct line between the centres of the sun and moon, would see a ring of light round the dark body of the moon; such an eclipse is called annular; when this happens there can be no total eclipse anywhere, because the moon's umbra does not reach the earth. An eclipse can never be annular longer than 12 minutes 24 seconds, nor total longer than 7 minutes 58 seconds; nor can the entire duration of an eclipse of the sun ever exceed 2 hours.
An eclipse of the sun begins on the western side of his disc and ends on the eastern; and an eclipse of the moon begins on the eastern side of her disc and ends on the western. The average number of eclipses in a year is four, two of the sun and two of the moon; and as the sun and moon are as long below the horizon of any particular place as they are above it, the average number of visible eclipses in a year is two, one of the sun and one of the moon. Research Eclipse
In chronology, epact is the excess of the solar month above the lunar synodical month, and of the solar year above the lunar year of twelve synodical months. The epacts then are annual and menstrual or monthly. Suppose the new moon to be on the 1st of January: the month of January containing 31 days, and the lunar month only 29 days, 12 hours, 44 minutes, 3 seconds; the difference, 1 day, 11 hours, 15 minutes, 57 seconds, is the menstrual epact. The annual epact is nearly 11 days; the solar year being 365 days, and the lunar year 354. The epacts were once of some importance in ecclesiastical chronology, being used for finding when Easter would fall. Research Epact
Etymologically a hypothesis is a supposition, and the term is popularly used to denote something not proved, but assumed for the sake of argument. In scientific and philosophical usage the term hypothesis denotes either a probable theory of phenomena not yet fully explained, or a strictly scientific theory which accounts for all the known facts of the case, and which only needs the verification of subsequent observations and deductions to become a certainty. Thus the conjecture of Isaac Newton that the force of gravity, as exemplified on the earth, might extend to the moon, was in its first stage a probable hypothesis; but when it was found to account for all the facts, it became a scientific hypothesis or theory. Research Hypothesis
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Almanac
