REVISED and IMPROVED from NOTES and MANUSCRIPTS of the New Discoveries, which have beer
(1860), furnished by PROF. NEWCOMB, of the Astronomical department at Cambr

PREFACE

TO THE REVISED EDITION.

TWELVE years have elapsed since the publication of this Illustrated Astronomy; during this time many new planets or Asteroids discovered; a notice of which will be found in its proper place; also a notice of Professor Bond's new theory in regard to Saturn's

The favor with which this work has been received by teachers and the public generally has far exceeded the author's expectations run through fifteen editions since its publication. It has been thoroughly revised, and the new discoveries are brought up to the pre five new illustrations have been added, and a new set of Electrotype plates have been procured at a great expense, which give a ve and beautiful diagram.

It has been the object of the author of this Illustrated Astronomy, to present all the distinguishing principles in physical Astrono few words as possible; but with such ocular demonstrations, by way of diagrams and maps, as shall make the subject easily underst letter press descriptions and the illustrations will invariably be found at the same opening of the book; and more explanatory cuts are at a much less price than have heen given in any other elementary Astronomy.

This work is designed for common schools, but may be used with advantage as an introductory work in high schools and academie preparation of these pages, most of the best works in our language have been consulted, and the best standard authorities, with reg discoveries and facts, have governed the author's decisions.

The Diagrams, which are larger and more full than those of any other work adapted to common schools, are most of them origin design, and exhibit the positions and phases of the planets in their orbits. The drawings being upon the principle of perspective, inclinations of their several axes to the planes of their orbits more correctly than has hitherto been done in any other popular work. to intimate to the young elementary student, who has made himself somewhat acquainted with the sublime mechanism of the solar sy there is something more magnificent beyond. Accordingly the author has given a few Sidereal Maps, just to awaken in the young the amazing conception, that unnumbered suns and revolving worlds occupy the depths of space far beyond the confines of our pla tem. By these maps he will be able to learn the relative positions of the principal constellations and stars, which will be found interesting to him in subsequent investigations of the ennobling truths of mathematical Astronomy.

The author is not so vain as to suppose that he has been able to present to teachers a faultless work; but in his own practice, find ous and often difficult to explain all the representable phenomena of the science on the black-board, and finding also a general conc opinion among teachers most interested in the study of Astronomy, that a cheap, compact, and illustrated work is necessary in ou schools, he has attempted the production of such a work. The success of the work and the favor with which it has been received, prove its superiority over all other works for the instruction of pupils in the general outlines of the science of Astronomy, and s author that he has not labored in vain in the production of this work.

Objections which are sometimes urged against questions and answers, in an elementary work, will not, the author hopes, be ur case, as the pupil has the subject, fully illustrated, continually before the eye, while he is learning his lesson.

To the teachers, of our common country, this work is most respectfully dedicated, in the sincere desire that the cause of educati benefited, and the labors of instruction in Astronomy may be rendered more easy and pleasant, from the illustrations it contains. ASA SMITH, Former Principal of Public School, No. 12, Seventeenth Street, near Eighth Avenue, City of New

7

INTRODUCTION TO ASTRONOMY.

LESSON I.

VHAT is the body called upon which we live?
It is called the EARTH, or WORLD.

dea had the ANCIENTS respecting the shape of the earth?
believed it was an extensive plain, rendered
hills and mountains.

id they think it was an extended plain?

use they formed their opinions from appear

ey believe that the earth had any motion?
did not; they believed that the earth rested
immovable foundation.

rally came to this conclusion, as they were entirely ignorant of the laws of
itation. They believed that if the earth were to turn over, that every thing
ited from its surface.]

hey any definite ideas respecting what held the earth up?
r views were very vague and unsatisfactory.

ben many absurd ideas advanced, at different ages of the world, as to what sup-
Some supposed it to be shaped like a CANOE, and to float upon the waters;
sted upon the back of an ELEPHANT or huge TURTLE; while, according to my-
pported it upon his shoulders: but, what kept the waters in their place, or upon
at, Turtle, or Atlas stood-this was a mystery they COULD NEVER SOLVE.]
they believe the earth extended the same distance in all

y believed it to extend much farther from east han from north to south.

d that in going east or west, on the same parallel of latitude, no change took earance of the heavens; but in going north or south, on the same meridian, every ed a difference of one degree in the elevation of the pole, and in the position of the notion of the sun and other heavenly bodies; therefore they concluded that the long from east to west, but comparatively narrow from north to south. From this use of the TERMS longitude and latitude; longitude meaning length, and latitude,

at ideas had they respecting the motions of the sun, moon, ey supposed that they revolved around the om east to west, every day..

at was this system called, that supposed the earth to be at centre, and all the heavenly bodies to revolve around it? ePtolemaic system.

erted, that the sun, moon, planets, and stars revolved around the earth, from east

Q. We see no body at rest that does not touch some permanent support, but we see bodies in motion supported for different lengths of time without resting upon any other surface; if the earth does not rest upon any thing, is it probably at rest?

A. It is more probable that it is in motion.

Q. If we throw a ball, does the same side always remain forward?
A. Not always; it sometimes turns round and round.
Q. What do we call the line round which it turns?

A. Its axis.

Q If a fly were on the ball, would distant objects appear to him to be stationary?

A. They would appear to revolve around the ball, as often as it turned over.

Q. If the earth is moving in space, is it in accordance with the known motion of ordinary bodies, to suppose that the same side remains forward? A. It is not. It is more reasonable to suppose that it turns on its axis.

Q. If the earth turns, and we are carried round on its surface, what appearance must the sun and distant stars necessarily present? A. They must appear to move around the earth in the opposite direction.

LESSON III.

Question. WHAT other reason can you give for the earth's turning? Answer. The stars are so distant, that their motion would be immensely swift in comparison with the motion of the earth, to produce the same effect.

Q. But have we not positive proof, and that too of different kinds, that the earth turns on its axis?

A. We have.-1. The shape of the earth, elevated at the equator and depressed at the poles, can be accounted for on no other supposition.

2. A body at the equator, dropped from a great

24 hours; and to account for their not falling upon the earth, when they passed height, falls eastward of the perpendicular.

posed that they were each fixed in a separate hollow crystalline globe, one within us the moon was in the first; Mercury in the second; Venus in the third; the sun 5 Mars in the fifth; Jupiter in the sixth; Saturn in the seventh; the planet not known at this time)-the fixed Stars in the eighth. He supposed the stars to re as they are kept in the same position with respect to each other. To permit the ars to pass down to the earth, he supposed these spheres or globes were perfectly parent like glass. The power which moved these spheres, he supposed, was comm above the sphere which contained the stars.]

n. EVERY one is conscious that the sun, which rises daily -t and sets in the west, is the same body; where does it go e night?

er. It appears to pass round under the earth.

Then we look out upon the stars, on successive evenings, they O have. a definite position with respect to each other, and a movement like the sun; what motion do they appear to n their setting to their rising?

hey appear to pass under the earth.

com the north to the south point of the heavens, there is a
us arc of stars, and in their passage under the earth they are

1 disarranged, what can you infer from this fact?
"hat they pass completely around the earth, and
hing attached to it.

3. The trade winds and ocean currents in the tropical regions are clearly traceable to the same cause.

Q. If the earth is moving in space, does it proceed in a straight line?

A. It does not; but it would do so, were it not attracted by other bodies.

Q. What is the attraction, by which all particles of matter tend towards each other, called?

A. The attraction of gravitation.

Q. What large body, by its attraction, causes the earth to revolve around it in a curvé line?