INTRODUCTORY—HISTORY OF ASTRONOMY—NOMENCLATURE.
Fig. 493.—Celestial globe.
Astronomy is the science which treats of the heavenly bodies and the laws which govern them. The term is derived from two Greek words, astron, a star, and nomos, a law. It may be included in the study of Physics, for the motion of the planetary bodies and equilibrium, gravity, etc., all have something to say to the arrangements and positions of the stars. The space in which they are set is infinite, and known as the “Firmament,” or “Heaven.” The number of the heavenly bodies must therefore be infinite also. We can see a few stars, comparatively speaking, and there must be numbers whose light has never yet reached the earth. When we calmly reason upon the immeasurable distances and the awful rapidity of motion, with the masses of matter thus in movement, we are constrained to acknowledge that all our boasted knowledge is as nothing in the wondrous dispensations of Him “who telleth the number of the stars, and calleth them all by their names.”
Astronomy, no more than any other of the physical sciences, cannot stand by itself. We have seen how heat, light, electricity, etc., are all, in a manner, inter-dependent. So astronomy is dependent upon mathematics, particularly geometry and trigonometry, for the wondrous problems to be solved. But in the following sketch we do not propose to plunge the reader in the slough of calculations. We only desire to put plainly before him the great phenomena of nature with regard to the heavens, and the glorious orbs which so thickly stud the space above us. We need not detail the laborious calculations by which philosophers have arrived at certain discoveries. We may refer to the results and explain general principles, thereby indicating the road by which the student may arrive at the more difficult bypaths in the fields of scientific discovery.
The history of astronomy is nearly as old as the world itself, or rather as old as the human race. From the earliest ages we can picture men gazing upon the “spangled heavens,” and the wandering tribes of the desert were always very careful observers of the paths of the stars. To the nomads of the East the planetary system served as compass and clock, calendar and barometer.
We shall find, therefore, that many observations of the heavenly bodies were made by the ancients, and have descended to more advanced generations, and this leads us to remark that the science of astronomy can be studied without any very special or costly apparatus. In other branches of science numerous instruments are indispensable before we can reveal to ourselves the desired results. In astronomy, a telescope—even a good field glass, such as possessed by any household, will reveal many interesting facts. We will, by means of more expensive instruments, and by the aid of large telescopes particularly, enjoy the sight of the moon and planets. But even with the naked eye a great variety of phenomena may be observed. With a celestial globe in our hands upon a fine starry night, we can easily find out the position of the constellations, and trace their forms in the firmament.
It is to the Chaldeans, Indians, Chinese, and Egyptians, that our knowledge of astronomy is primarily due. They did much to facilitate the observation of the stars; they named the planets, grouped the stars, and marked the sun’s track in the sky. Astrology was cultivated in very remote ages. The Jews practised it; and the astrologers of subsequent periods played very important parts in divining the future of individuals, and casting their horoscopes. Many of these so-called predictions came true, “because,” as was remarked by Pascal, “as misfortunes are common they” (the astrologers) “are often right,” as they foretold misfortune oftener than good fortune. Still the fact remains that occasionally a very startling prediction was made, and proved true; such, for instance, as the laying waste of Germany by Gustavus Adolphus, which was foretold by Tycho Brahé after his consideration of a certain comet, and the date of the king’s death was also correctly prophesied. Astrology, therefore, held a very considerable influence over the human race during the Middle Ages.
We can only give a very brief historical summary of the science. We know that the destinies of individuals and nations were at a very early period attributed to the influence of the stars. We read that “the stars in their courses fought against Sisera,” and many expressions surviving to the present time serve to remind us that the stars were at one time paramount in men’s minds. Thus we have the phrases—“unlucky star,” “born under a lucky star,” “mark my stars,” “moonstruck,” etc. Even the common term “consider”—to take counsel of the stars—is thus accounted for, and many men have a habit of looking up to the ceiling of a room or to the sky when thinking deeply—considering with the stars. “Contemplate” is another term signifying the same thing; for templum, a temple, was formerly a space marked upon the sky in imaginary lines, and traced on the ground in accordance with the supposed diagram. Thus temple became a place for heavenly “contemplation,” and by an easy transition to a place of worship. In our old poets’ writings we have many allusions to the influences of the stars.
“Now glowed the firmament