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REVISED and IMPROVED from Notes and MANUSCRIPTS of the New Discoveries, which have been made to the present date

(1860), furnished by Prof. NEWCOMB, of the Astronomical department at Cambridge, Mass.

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ILLUSTRATED ASTRONOMY.

CONTENTS. 626092

Page.

11

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ILLUSTRATIONS..

Orrery, with a view of the Solar System in the back ground,

ar System in the back ground. . - . . 6 | Uranus and Neptune, .
Solar System and Comparative Magnitudes,

Phases of the Moon ; Apparent Magnitude of the Sun and Moon,
Centripetal and Centrifugal force,

. . - 10 Telescopic View of the New Moon,
Kepler's Laws, - .

. . . 10

Telescopic View of the Full Moon, . . .
The Mean and True Place of a Planet,

Te escopic View of the Old Moon, -
Circle ; Eclipse ; Concentric Circles ; Circles not in the same plane, ..

Eclipses,
Cut Section of the Sun,

Moon's Nodes; Inferior and Superior Conjunction,
Spots on the Sun,

. 12 Inferior and Superior Planets ; Heliocentric Longitude,
Transits to the year 1900, ..

. 12 Greatest Number of Eclipses that can happen in a year,
Signs of the Zodiac,

Tides, and Moon-light at the Poles,
Mercury and Venus; Telescopic Views; Venus Morning and Evening Star, 16 Orbits of the Planets and Comets; Comets,
Earth and Definitions,

18 Refraction ; Parallax Light and Heat, .
Seasons; Summer and Winter Rays, Equinoctial and Solstitial Points, . View of the Earth's Orbit, as seen from the nearest fixed Star,
Aërolites and Meteors, . - - - - 22 Terrestrial and Celestial Globes, and Milky-way, .
Mars, Asteroids and Jupiter, . . . . . 24 Binary Systems; Quadruple Stars, .
Jupiter; Telescopic Views, &c. .

26 A Perpendicular and an Oblique View of our own Cluster or Firmament,
Saturn ; Saturn's Rings and Moons,

28 | Telescopic Views of remarkable Nebulæ and Cluster of Stars, .

53

63

59

SIDERE AL MAPS.
Description and use of the Sidereal Maps,


. 60 | Map of the Visible Heavens, from April 18th to July 21st..

• 67
Explanations, showing the manner of using the Maps,

Descriptions of the Constellations visible, from. July 22d to October 31st.
Directions for finding the North Star at any time,

. 60 Principal Stars visible, ard Times for Observation, from July 220 to Octo-.
Description of the Constellations visible from January 21st to April 17th,

ber 31st.
Principal Stars visible, and Times for Observation, from January 21st to Map of the Visible Heavens, from July 22d to October 31st..
April 17th,
.

Descriptions of the Constellations visible, from November 1st to January 20th. 73
Map of the Visible Heavens, from January 21st to April 17th

. 63 Principal Stars visible, and Times for Observation, from November 1st to
Descriptions of the Constellations visible from April 181h to July 21st. 65

January 20th.

• 74
Principal Stars visible, and Times for Observation, from April 181h to July 21st. 66 | Map of the Visible Heavens, from November 1st 10 January 20th. · 75

Entered according to Act of Congress, in the year 1849, by Ass SMITH, in the Clerk's Ofice of the District Court of the United States, for the Southern District of New York

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PRE FACE
TO THE REVISED EDITION.

TWELVE years have elapsed since the publication of this Illustrated Astronomy; during this time many new planets or Asteroids have been 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 rings.

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

It has been the object of the author of this Illustrated Astronomy, to present all the distinguishing principles in physical Astronomy with as few words as possible ; but with such ocular demonstrations, by way of diagrams and maps, as shall make the subject easily understood. The letter press descriptions and the illustrations will invariably be found at the same opening of the book ; and more explanatory cuts are given, and 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 academies. In the preparation of these pages, most of the best works in our language have been consulted, and the best standard authorities, with regard to new :: 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 original in their design, and exhibit the positions and phases of the planets in their orbits. The drawings being upon the principle of perspective, exhibit the inclinations of their several axes to the planes of their orbits more correctly than has hitherto been done in any other popular work. It is well to intimate to the young elementary student, who has made himself somewhat acquainted with the sublime mechanism of the solar system, that there is something more magnificent beyond. Accordingly the author has given a few Sidereal Maps, just to awaken in the young astronomer the amazing conception, that unnumbered suns and revolving worlds occupy the depths of space far beyond the confines of our planetary system. By these maps he will be able to learn the relative positions of the principal constellations and stars, which will be found useful and 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, finding it tedious and often difficult to explain all the representable phenomena of the science on the black-board, and finding also a general concurrence of opinion among teachers most interested in the study of Astronomy, that a cheap, compact, and illustrated work is necessary in our common schools, he has attempted the production of such a work. The success of the work and the favor with which it has been received, sufficiently prove its superiority over all other works for the instruction of pupils in the general outlines of the science of Astronomy, and satisfies the 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 urged in this 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 education may be 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 York.

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INTRODUCTION TO ASTRONOMY.

LESSON I.

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 Question. What is the body called upon which we live?

time without resting upon any other surface; if the earth does not Answer. It is called the EARTH, or WORLD.

rest upon any thing, is it probably at rest ? Q. What idea had the ANCIENTS respecting the shape of the earth ?

A. It is more probable that it is in motion. A. They believed it was an extensive plain, rendered Q. If we throw a ball, does the same side always remain forward ? uneven by hills and mountains.

A. Not always; it sometimes turns round and round. Q. Why did they think it was an extended plain?

Q. What do we call the line round which it turns ? A. Because they formed their opinions from appear A. Its axis. apces only.

Q If a fly were on the ball, would distant objects appear to him to Q. Did they believe that the earth had any motion ?

be stationary ? A. They did not; they believed that the earth rested A. They would appear to revolve around the ball, as on a solid, immovable foundation.

often as it turned over. They very naturally came to this conclusion, as they were entirely ignorant of the laws of Q. If the earth is moving in space, is it in accordance with the attraction or gravitation. They believed that if the earth were to turn over, that every thing wonki be precipitated from its surface.)

known motion of ordinary bodies, to suppose that the same side Q. Had they any definite ideas respecting what held the earth up?

remains forward ? A. Their views were very vague and unsatisfactory.

A. It is not. It is more reasonable to suppose that it (There have been many absurd ideas advanced, at different ages of the world, as to what sup

turns on its axis. ported the earth. Some supposed it to be shaped like a CANOE, and to float upon the waters; others, that it rested upon the back of an ELEPHANT or huge TURTLE; while, according to my . Q. If the earth turns, and we are carried round on its surface, what thology, Atlas supported it upon his shoulders : but, what kept the waters in their place, or upon what the Elephant, Turtle, or Atlas stood-this was a mystery they COULD NEVER SOLVE.)

appearance must the sun and distant stars necessarily present ? Q. Did they believe the earth extended the same distance in all A. They must appear to move around the earth in the directions ?

opposite direction. A. They believed it to extend much farther from east to weșt than from north to south. [They observed that in going east or west, on the same parallel of latitude, no change took

LESSON III. place in the appearance of the heavens; but in going north or south, on the same meridian, every sixty miles caused a difference of one degree in the elevation of the pole, and in the position of the circles of daily motion of the sun and other heavenly bodies; therefore they concluded that the Question. What other reason can you give for the earth's turning ? earth was very long from east to west, but comparatively narrow from north to south. From this originated the use of the TERMS longitude and latitude; longitude meaning length, and latitude,

Answer. The stars are so distant, that their motion breadth.]

would be immensely swift in comparison with the moQ. What ideas had they respecting the motions of the sun, moon,

tion of the earth, to produce the same effect. and stars ? A. They supposed that they revolved around the | Q. But have we not positive proof, and that too of different kinds,

that the earth turns on its axis ? earth, from east to west, every day.

A. We have.-1. The shape of the earth, elevated at Q. What was this system called, that supposed the earth to be at rest in the centre, and all the heavenly bodies to revolve around it?

the equator and depressed at the poles, can be acA. The Ptolemaic system.

counted for on no other supposition.

2. A body at the equator, dropped from a great (Ptolemy asserted, that the sun, moon, planots, and stars revolved around the earth, from east to west, every 24 boure; and to account for their not falling upon the earth, when they passed height, falls eastward of the perpendicular. over it, he supposed that they were each fixed in a separate hollow crystalline globe, one within the other. Taus the moon was in the first; Mercury in the second; Venus in the third; the sun 3. The trade winds and ocean currents in the tropiin the fourth; Mary in the fifth: Jupiter in the sixth ; Saturn in the seventh ;-(the planet Herschel was not known at this time the fixed stars in the eighth. He supposed the stars to cal regions are clearly traceable to the same cause. be in one sphere as they are kept in the same position with respect to each other. To permit the light of the stars to pass down to the earth, he supposed these spheres or globes were perfectly

Q. If the earth is moving in space, does it proceed in a straight clear or transparent like glass. The power which moved these spheres, he supposed, was commnunicated from above the sphere which contained the stars.]

line?

A. It does not; but it would do so, were it not

attracted by other bodies. LESSON II.

Q. What is the attraction, by which all particles of matter tend Question. Every one is conscious that the sun, which rises daily

towards" each other, called ? in the east and sets in the west, is the same body; where does it go

Å. The attraction of gravitation. during the night?

Q. What large body, by its attraction, causes the earth to revolve Answer. It appears to pass round under the earth. around it in a curve line ? Q. When we look out upon the stars, on successive evenings, they

ssive evenings, they A. The sun. appear to have a definite position with respect to each other, and a

Q. What other similar bodies revolve around the sun ? westward movement like the sun ; what motion do they appear to

A. The planets. haye from their setting to their rising? A. They appear to pass under the earth.

Q. What may we call the earth, when considered with regard to its Q. From the north to the south point of the heavens, there is a siz

size, shape, 'motions, &c. ? continuous are of stars, and in their passage under the earth they are

A. One of the planets. not ai all disarranged, what can you infer from this fact ?

Q. What science describes these characteristics of the earth, and d. That they pass completely around the earth, and 1 other heavenly bodies ? every thing attached to it.

aus

in the fifth: Jupine fixed stars in the spect to each other

other Maravenly bodies describes these

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