moon's nodes. At each revolution the node occurred further west, until after a cycle of about nineteen years, it had circulated in the same direction entirely round the ecliptic. Long and patiently did the astronomer watch and wait, each eclipse is duly observed, and its attendant circumstances are recorded, when, at last, the darkness begins to give way and a ray of light breaks in upon his mind. He finds that no eclipse of the sun ever occurs unless the new moon is in the act of crossing the sun's track. Here was a grand discovery.-He holds the key which he believes will unlock the dread mystery, and now, with redoubled energy, he resolves to thrust it into the wards and drive back the bolts.

To predict an eclipse of the sun, he must sweep forward, from new moon to new moon, until he finds some new moon which should occur, while the moon was in the act of crossing from one side to the other of the sun's track.-This certainly was possible. He knew the exact period from new moon to new moon, and from one crossing of the ecliptic to another. With eager eye he seizes the moon's place in the heavens, and her age, and rapidly computes where she will be at her next change. He finds the new moon occurring far from the sun's track; he runs round another revolution; the place of the new moon falls closer to the sun's path, and the next yet closer, until reaching forward with piercing intellectual vigor, he at last, finds a new moon which occurs precisely at the computed time of her passage across the sun's track. Here he makes his stand, and on the day of the occurrence of that new moon, he announces to the startled inhabitants of the world, that the

sun shall expire in dark eclipse-Bold prediction !-Mysterious prophet! with what scorn must the unthinking world have received this solemn declaration. How slowly do the moons roll away, and with what intense anxiety does the stern philosopher await the coming of that day which should crown him with victory, or dash him to the ground in ruin and disgrace. Time to him moves on leaden wings; day after day, and at last hour after hour, roll heavily away. The last night is gone-the moon has disappeared from his eagle gaze in her approach to the sun, and the dawn of the eventful day breaks in beauty on a slum bering world.

'This daring man, stern in his faith, climbs alone to to his rocky home, and greets the sun as he rises and mounts the heavens, scattering brightness and glory in his path. Beneath him is spread out the populous city, already teeming with life and activity. The busy morning hum rises on the still air and reaches the watching place of the solitary astronomer. The thousands below him, unconscious of his intense anxiety, buoyant with life, joyously pursue their rounds of business, their cycles of amusement. The sun slowly climbs the heavens, round and bright and full orbed. The lone tenant of the mountain-top almost begins to waver in the sternness of his faith, as the morning hours roll away. But the time of his triumph, long delayed, at length begins to dawn; a pale and sickly hue creeps over the face of nature. The sun has reached his highest point, but his splendor is dimmed, his light is feeble. At last it comes !-Blackness is eating away his round disc,-onward with slow but steady pace, the dark veil moves, blacker than a thous

and nights,—the gloom deepens, the ghastly hue of death covers the universe,-the last ray is gone, and horror reigns. A wail of terror fills the murky air,the clangor of brazen trumpets resounds,-an agony of despair dashes the stricken millions to the ground, while that lone man, erect on his rocky summit, with arms outstretched to heaven, pours forth the grateful gushings of his heart to God, who had crowned his efforts with triumphant victory. Search the records of our race, and point me, if you can, to a scene more grand, more beautiful. It is to me the proudest victory that genius ever won. It was the conquering of nature, of ignorance, of superstition, of terror, all at a single blow, and that blow struck by a single arm.And now do you demand the name of this wonderful man! Alas! what a lesson of the instability of earthly fame are we taught in this simple recital.—He who had raised himself immeasurably above his race,—who must have been regarded by his fellows as little less than a god, who had inscribed his fame on the very heavens, and had written it in the sun, with a "pen of iron, and the point of a diamond," even this one has perished from the earth-name, age, country, are all swept into oblivion, but his proud achievement stands. The monument reared to his honor stands, and although the touch of time has effaced the lettering of his name, it is powerless, and cannot destroy the fruits of his victory.

A thousand years roll by: the astronomer stands on the watch tower of old Babylon, and writes for posterity the records of an eclipse; this record escapes Jestruction, and is safely wafted down the stream of ime.

A thousand years roll away: the old astrono⚫

mer, surrounded by the fierce, but wondering Arab again writes, and marks the day which witnesses the sun's decay. A thousand years roll heavily away : once more the astronomer writes from amidst the gay throng that crowds the brightest capital of Europe. Record is compared with record, date with date, rev· olution with revolution, the past and present are link ed together, another struggle commences, and another victory is won. Little did the Babylonian dream, that he was observing for one who after the lapse of 3000 years, should rest upon this very record, the successful resolution of one of nature's darkest mysteries.

We have now reached the boundary where the stream of discovery, which we have been tracing through the clouds and mists of antiquity, begins to emerge into the twilight of tradition, soon to flow on in the clear light of a history that shall never die. Henceforth our task will be more pleasing, because more certain; and we invite you to follow us as we attempt to exhibit the coming struggles and future triumphs of the student of the skies.

LECTURE III.

TUFORIES FOR THE EXPLANATION OF THE MOTIONS OF

THE HEAVENLY BODIES.

IF in tracing the career of astronomy in the primitive ages of the world, we have been left to pursue our way dimly, through cloud and darkness,-if regrets rise up, that time has swept into oblivion the names and country of the early discoverers, in one re flection there is some compensation—while the bright and enduring truths which they wrested from nature have descended to us, their errors, whatever they may have been, are forever buried with their names and their persons. We are almost led to believe that those errors were few and transient, and that the mind, as yet undazzled by its triumphs, questioned nature, with that humility and quiet perseverance, which could bring no response but truth.

In pursuing the consequences flowing from the prediction of an eclipse, several remarkable results were reached, which we proceed to unfold. It will be recollected, that to produce either solar or lunar eclipses, the new or full moon must be in the act of crossing the sun's annual track. This point of crossing, called the moon's node, became therefore an object of the deepest interest. Long and careful scrutiny revealed the fact of its movement around the ecliptic, in a period