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
The Morris Minor was a series of incredibly popular British small cars first shown at the 1948 Earl' s Court Motor Show, and the first British car to reach a production of one million, with a total of 1.6 million cars made until production stopped in 1971. The Morris Minor was designed by Alec Issigonis who worked for the Nuffield Organisation owned by William Morris (LordNuffield). Originally designed to be powered by an 1100cc flat-four water-cooled engine, the Morris Minor was fitted with the same 918cc side valve engine as had been used successfully in the Morris Eight series E car, resulting in space in the engine compartment which made the Morris Minor a very easy car to maintain. Today the Morris Minor has a cult status with enthusiasts and fan clubs. Research Morris Minor More information about Morris Minor
Originally, a punkah was a portable fan made from the leaf of the palmra, but in Anglo-Indian parlance a large fixed and swinging fan formed of cloth attached to a rectangular frame suspended from the ceiling and pulled backwards and forwards by means of a cord, thus causing a current of air in the apartment. Research Punkah
Alcyonaria are coelenterate animals forming a great division of the class Actinozoa. These animals are nearly all composite, and the individual polyps have mostly eight tentacles. They include the organ-pipe corals, sea-pens, fan-corals, etc, as also the red coral of commerce. The polyps essentially resemble those of the genusAlcyonium in structure, and in the number and arrangement of the tentacles. Research Alcyonaria
The Buriti (Mauritia vinifera) is a South American palm growing to about 50 metres. It prefers marshy situations, and bears an imposing crown of fan- shaped leaves. A sweet vinous liquor is prepared from the juice of the stem as also from the fruits. Research Buriti
Chamaerops is a genus of palms belonging to the northern hemisphere and consisting of dwarf trees with fan-shaped leaves borne on prickly petioles and a small berry-like fruit with one seed. The Chamaerops humilis is the only native European palm. It does not extend further north than Nice. The fibres of its leaves form an article of commerce under the name of crin vegetal (vegetable hair). Brazilian grass is a fibre obtained from the Chamaerops argentea. A Chinese species, Chamaerops Fortunei, is quite hardy in the south of England. Research Chamaerops
The Cycads are a family of tropical trees and shrubs with usually simple, sometimes dichotomous trunks marked with leaf scars, and resembling palms and tree ferns. The leaves are pinnate, and curled in the bud-like fan fronds. The flowers are always terminal, resembling cones. Research Cycad
The Doum Palm (Hyphoene thebaica) is a species of palm tree. It is remarkable, like the other species of the genus, for having a repeatedly-branched stem. Each branch terminates in a tuft of large fan-shaped leaves. The fruit is about the size of an apple; it has a fibrous mealy rind, which tastes like gingerbread (whence the name gingerbread tree sometimes applied to this palm), and is eaten by the poorer inhabitants of Upper Egypt, where it grows. An infusion of the rind is also used as a cooling beverage in fevers. The seed is horny, and is made into small ornaments. Ropes are made of the fibres of the leaf-stalks. Research Doum Palm
The Earwig (Forifculidae) is a family of the order Dermaptera. The body is narrow and terminates in characteristic forceps which are used in folding the hind wings after use. The fore wings are modified into wing covers, and are short and rectangular. Beneath them lie the rarely used hind wings, which are elaborately folded after the manner of a fan. The young are similar in appearance to their parents but smaller and without wings. The common earwig is Forficula auricularia and is found all over Europe.
The earwig gets its name from its supposed habit of insinuating itself into the ears of persons. This is practically impossible, yet the notion was widely spread, as appears from the names given to the earwig in different languages, as in French perceoreille (pierce-ear) and in German ohrenhohler (ear-borer). Research Earwig
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