CONTENTS.

LECTURE I.

AN EXPOSITION OF THE PROBLEM WHICH THE HEAVENS PRESENT

FOR SOLUTION

LECTURE II.

THE DISCOVERIES OF THE PRIMITIVE AGES

LECTURE III.

THEORIES FOR THE EXPLANATION OF THE MOTIONS OF THE

HEAVENLY BODIES

ANCIENT AND MODERN IDEAS ON THE SYSTEM OF THE WORLD

STATUE OF NEWTON, IN THE ANTE-CHAPEL, TRIN. COLL., CAMBRIDGE

19

PLATO

46

COPERNICUS

49

(From a picture in the possession of the Royal Society, presented by Dr. Wolf of

Dantzic, June 6, 1776.)

(Inventor of the reflector telescope, from an original in the possession of Mr. Carnegy,

Aberdeen, N.B. Published 1798.)

(From the original picture by Vanderbank, in the possession of the Royal Society.)

BIRTH-PLACE OF NEWTON, WOOLTHORPE, LINCOLNSHIRE.

75

HALLEY'S COMET, AS SEEN BY SIR JOHN F. HERSCHEL, OCTOBER

29TH, 1835

HALLEY'S COMET, AS SEEN BY STRUVE, OCTOBER 12TH, 1835

SIR. J. F. HERSCHEL, BART., F.R.S. (From a portrait by H. W. Pickersgill.)

THE GREAT COMET OF 1744 .

M. ARAGO. (From a Daguerreotype by Claudet.)

THE

ORBS OF HEAVEN.

INTRODUCTORY.

AN EXPOSITION OF THE PROBLEM WHICH THE HEAVENS
PRESENT FOR SOLUTION.

HE subject to which your attention is invited, claims no specific connection with the every day struggle of human life. Far away from the earth on which we dwell, in the blue ocean of space, thousands of bright orbs, in clusterings and configurations of exceeding beauty, invite the upward gaze of man, and tempt him to the examination of the wonderful sphere by which he is surrounded. The starry heavens do not display their glittering constellations in the glare of day, while the rush and

turmoil of business incapacitate man for the enjoyment of their solemn grandeur. It is in the stillness of the midnight hour, when all nature is hushed in repose, when the hum of the world's on-going is no longer heard, that the planets roll and shine, and the bright stars, drooping through the deep heavens, speak to the willing spirit that would learn their mysterious being.

B