HISTORY OF PHYSICAL ASTRONOMY.

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seldom fails to arouse the apathy of the most listless votary of nature.But perhaps on no occasion does the display of stupendous power in theeconomy of the physical universe exercise so subduing an influence overthe mind, or produce so humiliating a conviction of the impotence of allhuman efforts to control the immutable laws of nature, and arrest thecourse of events, as when the glorious orb of day, while riding in the heavens with unclouded splendour, begins to melt away from an unseen cause,and soon totally disappears, leaving the whole visible world wrapped inthe sable gloom of nocturnal darkness. The scene is rendered still moreimpressive by the circumstances accompanying so remarkable an occur-rence. The heavens assume an unnatural aspect, which excites a feelingof horror in the spectator; a livid hue is diffused over all terrestrialobjects ; the plants close up their leaves as on the approach of night; thefowls betake themselves to their resting-places ; the warbling of the groveis hushed in profound silence. Universal nature seems to have relaxedher energies, as if the pulse which stimulated her mighty movements hadall at once stood still.

During the early history of mankind, a total eclipse of the sun wasinvariably regarded with a feeling of indescribable terror, as an indicationof the anger of the offended deity, or the presage of some impendingcalamity; and various instances are recorded of the extraordinary effectsproduced by so unusual an event. In a more advanced state of so-ciety, when science had begun to diffuse her genial influence over thehuman mind, these vain apprehensions gave place to juster and moreennobling views of nature; and eclipses generally came to be lookedupon as necessary consequences flowing from the uniform operation offixed laws, and differing from the ordinary phenomena of nature, onlyin their less frequent occurrence. To the astronomer they have in allages proved valuable in the highest degree, as tests of great delicacyfor ascertaining the accuracy of his calculations relative to the place ofthe moon, and hence deducing a further improvement of the intricatetheory of her movements. In modern times, when the physical consti-tution of the celestial bodies has attracted the attention of many emi-nent astronomers, observations of eclipses have disclosed several in-teresting facts, which have thrown considerable light on some importantpoints of enquiry respecting the sun and moon.

In the present advanced state of astronomy, the records of ancienteclipses have been successfully employed in fixing the dates of contem-porary events, and thereby rescuing history, in many instances, from theconfusion usually incident to a remote antiquity. It is thus that pheno-mena, which, at the time of their apparition, were regarded as themysterious heralds of some impending calamity in the moral world,totally independent of the ordinary course of nature, and which wouldhave been allowed to pass unnoticed, had it not been for the terror whichthey inspired, have become subservient in illustrating many obscure pas-sages in the writings of the persons who record them, and establishingour knowledge of ancient times upon a more satisfactory basis. This isjustly regarded as one of the most remarkable triumphs of modern science.

Before entering upon the history of total eclipses of the sun it may notbe out of place to give a brief description of the nature of eclipses ingeneral, and of the various circumstances which determine their occur-rence.

The moon, in the course of her monthly revolution round the earth,