Of all the natural sciences there is not one which offers such sublime objects to the
attention of the inquirer as does the science of astronomy. From the earliest ages the
study of the stars has exercised the same fascination as it possesses at the present day.
Among the most primitive peoples, the movements of the sun, the moon, and the stars
commanded attention from their supposed influence on human affairs.
The practical utilities of astronomy were also obvious in primeval times. Maxims of
extreme antiquity show how the avocations of the husbandman are to be guided by the
movements of the heavenly bodies. The positions of the stars indicated the time to
plough, and the time to sow. To the mariner who was seeking a way across the trackless
ocean, the heavenly bodies offered the only reliable marks by which his path could be
guided. There was, accordingly, a stimulus both from intellectual curiosity and from
practical necessity to follow the movements of the stars. Thus began a search for the
causes of the ever-varying phenomena which the heavens display.
Many of the earliest discoveries are indeed prehistoric. The great diurnal movement of
the heavens, and the annual revolution of the sun, seem to have been known in times far
more ancient than those to which any human monuments can be referred. The acuteness
of the early observers enabled them to single out the more important of the wanderers
which we now call planets. They saw that the star-like objects, Jupiter, Saturn, and Mars,
with the more conspicuous Venus, constituted a class of bodies wholly distinct from the
fixed stars among which their movements lay, and to which they bear such a superficial
resemblance. But the penetration of the early astronomers went even further, for they
recognized that Mercury also belongs to the same group, though this particular object is
seen so rarely. It would seem that eclipses and other phenomena were observed at
Babylon from a very remote period, while the most ancient records of celestial
observations that we possess are to be found in the Chinese annals.
The study of astronomy, in the sense in which we understand the word, may be said to
have commenced under the reign of the Ptolemies at Alexandria. The most famous name
in the science of this period is that of Hipparchus who lived and worked at Rhodes about
the year 160BC. It was his splendid investigations that first wrought the observed facts
into a coherent branch of knowledge. He recognized the primary obligation which lies on
the student of the heavens to compile as complete an inventory as possible of the objects
which are there to be found. Hipparchus accordingly commenced by undertaking, on a
small scale, a task exactly similar to that on which modern astronomers, with all available
appliances of meridian circles, and photographic telescopes, are constantly engaged at the
present day. He compiled a catalogue of the principal fixed stars, which is of special
value to astronomers, as being the earliest work of its kind which has been handed down.
He also studied the movements of the sun and the moon, and framed theories to account
for the incessant changes which he saw in progress. He found a much more difficult
problem in his attempt to interpret satisfactorily the complicated movements of the
planets. With the view of constructing a theory which should give some coherent account