"Perhaps there is not in Nature a more exhilarating sight, or one more strongly exciting to confidence in God, than the rise of the Nile. Day by day, night by night, its turbid tide sweeps onward majestically over the parched sands of the waste howling wilderness. Almost hourly, as we slowly ascended it before the Etesian wind, we heard the thundering fall of some mud bank, and saw by the rush of all animated Nature to the spot, that the Nile had overleapt another obstruction, and that its bounding waters were diffusing life and joy through another desert."
After the flood comes sowing time and the effects of it all are exhibited:
"in a scene of fertility and beauty such as will scarcely be found in another country at any season of the year. The vivid green of the springing corn, the groves of pomegranate trees ablaze with the rich scarlet of their blossoms, the fresh breeze laden with the perfumes of gardens of roses and orange thickets, every tree and every shrub covered with sweet-scented flowers."
No wonder that the appearance of Sirius was hailed with reverence when its rising just before the sun meant also the rise of the life-giving river and the prosperity of the inhabitants of Egypt! However, as mentioned before, with the precession of the equinoxes, the heliacal rising of Sirius has changed and its brilliant light no longer announces the rising of the Nile.
Sirius is one of our nearest stars for its light requires only 8½ years to reach the earth. Yet its nearness does not account altogether for its quite exceptional brightness, for our sun at the same distance would appear as a star of the 6th magnitude and be invisible to the unaided eye. Only two stars, as far as has yet been discovered, lie closer to the earth than Sirius. The second brightest star in the sky is Canopus, visible from the southern hemisphere, but so far away that its distance can scarcely be estimated.
Halley, a celebrated English astronomer born 1656, made the first discovery of the relative motion of the stars when he noted that Sirius had moved from the position assigned to it on Ptolemy's map of 150 A. D. We have now reliable data for discussing the proper motion of about 10,000 stars. The proper motion of stars consists of a displacement in various directions of the individual stars. Thus the configuration of a constellation may slowly change, and, although many groups of stars all travel in the same direction, there are also conspicuous instances where they move in different directions. The Big Dipper and the Southern Cross are two star groups whose stars are traveling along different courses and after a period of time extending over thousands of years, the 'dipper' and the 'cross' effect of these two constellations will have altogether disappeared.
For a while Sirius was believed to be traveling in a straight line, but soon irregularities were discovered in the great star's motion, an "undulatory progressive motion" on each side of a middle line. From a knowledge of these oscillating movements, Bessel inferred that Sirius must have an unseen companion attracting or pulling it as the two stars traveled together around a common center of gravity. In 1862, Mr. Alvan G. Clarke of New York detected this companion situated at an angular distance of only 7" from Sirius,—about as far distant as Uranus is from the earth. The larger star is only about twice as massive as its companion but is 20,000 times brighter. The light that we see from Sirius then comes from two stars which together radiate 48 times as much light as the sun. Compared to Sirius, our sun is rather an inconspicuous star, although Barnard gave us great satisfaction by discovering a neighbor not much farther away than Sirius which gives out only ¹⁄₂₅₀₀ as much light as the sun!
Sirius, the "Dog Star," rests on the nose of the Great Dog, in the constellation Canis Major, and may be found in a straight line from the three evenly spaced stars in Orion's Belt. He was originally Orion's hunting dog, and, as if to give atmosphere to a hunting scene in the sky, Lepus, the Hare, has been placed on a constellation just in front of Sirius and below the feet of Orion, where he is "pursued continually through all time" by the Dog with the huge star.
A vividly red variable star glows in the constellation of Lepus, the Hare. Every so often, this little star becomes radiantly red. This additional light is caused by the star bursting explosively through the layer of absorbent vapors which are smothering the life from its flames. Some day this crimson star will flare and flicker for the last time and its final ray be wafted to our earth—the Swan Song of a dying star.
About 9 o'clock during the first part of December, Sirius rises on its pathway south of east, the brilliant beauty of its light adding to the celestial scene like a torch among a thousand candles. This is true though the month of December exhibits the loveliest assembly of stars to be seen in all the year.