the occurrence of an annular or total one at any particular locality is a very rare phenomenon. Thus, according to Halley', no total eclipse had been observed at London between March 20, 1140, and April 22, 1715 (0. s.), though during that interval the shadow of the Moon had frequently passed over other parts of Great Britain". The calculation of eclipses is a matter of considerable complexity. A paper by Woolhouse, in the supplement to the Nautical Almanac for 1836, and the chapters in Loomis's well-known work", may be named as the best guides in our language. Much interesting historical matter concerning eclipses will be found in the Rev. S. J. Johnson's Eclipses, Past and Present. 1 Phil. Trans., vol. xxix. p. 245. 1715. m It may here be noted that, according to recent investigations by Hind, the Total solar eclipse of Feb. 3, 1916, will not be visible as such in England, though a statement to that effect may occasionally be met with. On June 30, 1954, occurs the next Total eclipse which will be visible in Great Britain; this will be seen at the northernmost of the Shetland Isles. The eclipse of Aug. 11, 1999, is the next that will be visible as a Total one in England itself. The line of totality will pass across Cornwall and Devonshire. Hind, in connection with the calculations from which these particulars were derived, ascertained that the eclipse of CHAPTER II. ECLIPSES OF THE SUN. Grandeur of a Total Eclipse of the Sun.-How regarded in ancient times.Effects of the progress of Science.-Indian Customs.-Effect on Birds at Berlin in 1887.-Solar Eclipses may be Partial, Annular, or Total.-Chief phenomena seen in connexion with Total Eclipses.-Change in the colour of the sky.-The obscurity which prevails.-Effect noticed by Piola.-Physical explanation.— Baily's Beads.-Extract from Baily's original memoir.-Probably due to irradiation. Supposed to have been first noticed by Halley in 1715.—His description. --The Corona.-Hypothesis advanced to explain its origin.—Frobably caused by an atmosphere around the Sun.—Remarks by Grant.—First alluded to by Philostratus.-Then by Plutarch.-Corona visible during Annular Eclipses.— The Red Flames.-Remarks by Dawes.-Physical cause unknown.-First mentioned by Stannyan.-Note by Flamsteed.-Observations of Vassenius.— Aspect presented by the Moon.-Remarks by Arago. A TOTAL eclipse of the Sun is a most imposing spectacle, especially when viewed from the summit of a lofty mountain, and the moon's shadow is seen sweeping upward from the horizon towards the observer with a velocity which has been described as perfectly frightful. Professor Forbes, who observed the total eclipse of 1842 from the Observatory of Turin, was so confounded by the frightful velocity with which the shadow swept over the earth from the distant Alps towards him that he felt as if the great building on which he was standing was commencing to fall over in the direction of the coming darkness. Words can but inadequately describe the grandeur and magnificence of the scene. On all sides indications are afforded that something unusual is taking place. At the moment of totality the darkness is usually so intense that the brighter planets and stars of the 1st and 2nd magnitude are seen, birds go to roost, flowers close, and the face of nature assumes an unearthly cadaverous hue; while not the least striking thing is the sudden gust of wind which frequently sweeps over the country with some violence at the commencement of totality; sometimes a considerable fall takes place in the temperature of the atmosphere as the time of the greatest obscuration draws near. "During the early history of mankind, a total eclipse of the Sun was invariably regarded with a feeling of indescribable terror, as an indication of the anger of the offended Deity, or the presage of some impending calamity; and various instances are on record of the (supposed) extraordinary effects produced by so unusual an event. In a more advanced state of society, when Science had begun to diffuse her genial influence over the human mind, these vain apprehensions gave place to juster and more ennobling views of nature; and eclipses generally came to be looked upon as necessary consequences flowing from the uniform operation of fixed laws, and differing from the ordinary phenomena of nature only in their less frequent occurrence. To astronomers they have in all ages proved valuable in the highest degree, as tests of great delicacy for ascertaining the accuracy of their calculations relative to the place of the Moon, and hence deducing a further improvement of the intricate theory of her movements. In modern times, when the physical constitution of the celestial bodies has attracted the attention of many eminent astronomers, observations of eclipses have disclosed several interesting facts, which have thrown considerable light on some important points of inquiry respecting the Sun and Moon "." Among the Hindus a singular custom exists". When during a Grant, Hist. Phys. Ast., p. 359. The truth of the last sentence of this extract is now more striking than it was in 1852. b In my first edition I wrote "is said to exist," but the following paragraph, cut from a newspaper in 1868, and relating to the great eclipse of Aug. 18, 1868, will shew that the present reading of the text is preferable :-" Tuesday was a general holiday, and the natives signified the swallowing of the sun by a demon by the usual drumming, shrieking, and blowing of shells, with offerings of rice." Nor is this an isolated incident. The following account was written of the eclipse of the Sun of July 29, 1878, by a resident at Fort Sill, Indian Territory, to Mr. Fox, Ex-Mayor of Philadelphia, U.S., who allowed its publication in the a solar eclipse the black disc of our satellite is seen advancing over the Sun, the natives believe that the jaws of some monster are gradually eating it up. They then commence beating gongs, and rending the air with the most discordant screams of terror and shouts of vengeance. For a time their efforts are productive of no good result-the eclipse still progresses. At length, however, the terrific uproar has the desired effect on the voracious monster; it appears to pause, and then, like a fish that has nearly swallowed a bait and then rejects it, it gradually disgorges the fiery mouthful. When the Sun is quite clear of the great dragon's mouth, a shout of joy is raised, and the poor natives disperse, extremely self-satisfied on account of their having (as they suppose) so successfully relieved their deity from his late perils. For us times have now happily altered. We do not look on a total eclipse of the Sun as a dire calamity, but merely as one of the ordinary effects resulting from the due working of those laws by which the Supreme Being wills to govern the universe. The Eclipse of Aug. 19, 1887, deficient though it was in Astronomical results, yielded some rather interesting observations with respect to the effect of the eclipse on birds. In N. E. Germany, foresters stated that the birds, which had already begun to sing before the eclipse took place, became of a sudden quite silent, and Philadelphia Inquirer:-" On Monday last we were permitted to see the eclipse of the sun in a beautiful bright sky. Not a cloud was visible. We had made ample preparation, laying in a stock of smoked glass several days in advance. It was the grandest sight I ever beheld, but it frightened the Indians badly. Some of them threw themselves upon their knees and invoked the Divine blessing; others flung themselves flat on the ground face downward; others cried and yelled in frantic excitement and terror. Finally one old fellow stepped from the door of his lodge, pistol in hand, and fixing his eyes on the darkened sun mumbled a few unintelligible words, and raising his arm, took direct aim at the luminary, fired off his pistol, and after throwing his arms about his head in a series of extraordinary gesticulations, retreated to his own quarters. As it happened that very instant was the conclusion of totality. The Indians beheld the glorious orb of day once more peep forth, and it was unanimously voted that the timely discharge of that pistol was the only thing that drove away the shadow and saved them from the public inconvenience that would have certainly resulted from the entire extinction of the sun." See for recent instances of popular excitement at eclipses, 2 engravings and narratives in L'Astronomie, vol. vi. p. 248, July 1887, and relating to the eclipses of Dec. 16, 1880, and March 1, 1877, as seen at Tashkend and Laos (Indo-China) respectively. showed signs of disquiet when darkness set in. Herds of deer ran about in alarm, as did the small four-footed game. In Berlin a scientific man arranged for observations to be made by birddealers of the conduct of their feathered stock. The results were found to vary considerably. In some cases the birds shewed sudden sleepiness, even though they had sung before the eclipse took place. In other cases great uneasiness and fright were observed. Parrots shewed far more susceptibility than canaries, becoming totally silent during the eclipse, and only returning very slowly to their usual state. An eclipse of the Sun may be either partial, annular, or total : it is partial when only a portion of the Moon's disc intervenes between the Sun and the observer on the Earth; annular, when the Moon's apparent diameter is less than the Sun's, so that when the former is projected on the latter it is not sufficiently large completely to cover it,-an annulus, or ring of the Sun, being left unobscured; and total when the Moon's apparent diameter is greater than that of the Sun, which is, therefore, wholly obscured. In an annular eclipse, when the centre of the Sun and Moon exactly coincide, it is said to be central and annular—the Sun appearing, for a very short time, as a brilliant ring of light around the dark body of the Moon. I shall now proceed to describe the principal phenomena which are usually witnessed in connexion with solar eclipses. Not the least remarkable is the almost invariable change of colour which the sky undergoes. Halley, in his account of the eclipse of 1715, says: "When the eclipse was about 10 digits (that is, when about of the solar diameter was immersed), the face and colour of the sky began to change from a perfect serene azure blue to a more dusky livid colour, intermixed with a tinge of purple, and grew darker and darker till the total immersion of the Sun"." At the moment of totality the suddenly altered conditions of illumination give rise to a further change of colour which is so e Phil. Trans., vol. xxix. p. 247. 1715. Arago gives an elaborate explanation of this. Pop. Ast., vol. ii. p. 358, Eng. ed. T |