A fourteen weeks course in descriptive astronomy

Front matter

She National Series

FXJBLISHEID BT^

111 & 113 WILLIAM STEEET, NEW YORK.

Preface

During tlie past few years great advances have been made in astronomical science. A new horizontal parallax of the sun has been established. This has materially altered the estimated distances, etc., of the planets. The sun is much nearer us than we supposed, and light has lost a little of its wonderful velocity. Much additional information has been obtained concerning Meteors and Shooting Stars. The investigations connected with Spectrum Analysis have been especially suggestive. Thus on every hand the facts of Astronomy have been accumulating. As yet, however, they are scattered through many expensive foreign works, and are consequently beyond the reach of most of our schools. It has been the aim of the author to collect in this little volume the most interesting features of these larger works. Believing that Natural Science is full of fascination, he has sought to weave the story of those far-distant worlds into a form that may attract the attention and kindle the enthusiasm of the pupil. The work is not written for the information of scientific men, but for the inspiration of youth. The pages therefore are not burdened with a multitude

6 PREFACE.

of figures which no memory could possibly retain. Mathematical tables and data, Questions for Review, and also a Guide to the Constellations, are given in the Appendix, where they may be useful for constant reference.

The author would call particular attention to the method of classifying the measurements of Space, and the practical treatment of the subjects of Parallax, Harvest Moon, Eclipses, the Seasons, Phases of the Moon, Time, Nebular Hypothesis, &c.

To teachers heretofore compelled to use a cumbersome set of charts, it is hoped that the star maps here offered will present a welcome substitute. The geometrical figures showing the actual appearance of the constellations, will relieve the mind confused with the idea of numberless rivers, serpents, and classical heroes. The brightest stars only are given, since in practice it is found that pupils remember the general outlines alone.

Finally, the author commits this Httle work to the hands of the young, to whose instruction he has consecrated the energies of his life, in the earnest hope that, loving Nature in all her varied phases, they may come to understand somewhat of the wisdom, power, beneficence, and grandeur displayed in the Divine harmony of the Universe.

" One God, one law, one element,

And one far-off Divine event

To wMcli the whole creation moves."

PKEFACE. 7

The following works, among others, have been Ireely consulted in preparing this volume :

The Heavens Guillemin.

Astronomy Chambers.

Introduction to Astronomy Hind

Solar System Hind.

Popular Asti'onomy Airy.

Popular Astronomy Arago,

Astronomy Norton.

Asti'onomy Robinson.

Astronomy Loomis.

Age of Fable Bulfinch.

Poetry of Science Hunt.

Outlines of Astronomy Herschel.

Popular Astronomy Mitchell.

Astronomy and Physics Whewell.

Annual of Scientific Discovery Kneeland

The Chemical News.

SUGGESTIONS TO TEACHERS.

This Tvork is designed to be recited in the topical method. On naming the title of a paragraph, the pupil should be able to draw on. the blackboard the diagram, if any is given, and state the substance of what is contained in the book. It will be noticed that the order of topics, in treating of the planets and also of the constellations, is uniform. If a portion of the class vnite then* topics in full upon the blackboard, it will be found a valuable exercise in spelling, punctuation, and composition. Every point which can be illustrated in the heavens should be shown to the class. No description or apparatus can equal the reality in the sky. After a constellation has been traced, the pupil should be practised in star-map drawing. Much profitable instruction can be obtained in this way. For the purpose of more easily finding the heavenly bodies at any time, Whit all's Movable Planisphere is of great service. It may be procm-ed of the publishers of this work. " Orreries are of little account." A tellurian is invaluable in explaining Precession of the Equinoxes, Eclipses, Phases of the Moon, etc. Messrs. J. Nellegar & Co., Albany, N. Y., furnish a good instrument at a low price. The article on " Celestial Measm-ements," near the close of the work, should be constantly referred to during the term. In the figures, the right-hand side represents the west and the left-hand the east. When it is important to obtain this idea correctly, the book should be held up toward the southem sky.

Table Of Contents

CELESTIAL MAP.

L INTRODUCTION.

PAGB