History of Astronomy | Page 2

bodies.
These reflections, arising from the writing of this History, go to explain
the invariable humility of the great mathematical astronomers.
Newton's comparison of himself to the child on the seashore applies to
them all. As each new discovery opens up, it may be, boundless oceans
for investigation, for wonder, and for admiration, the great astronomers,
refusing to accept mere hypotheses as true, have founded upon these
discoveries a science as exact in its observation of facts as in theories.
So it is that these men, who have built up the most sure and most solid
of all the sciences, refuse to invite others to join them in vain
speculation. The writer has, therefore, in this short History, tried to
follow that great master, Airy, whose pupil he was, and the key to
whose character was exactness and accuracy; and he recognises that
Science is impotent except in her own limited sphere.
It has been necessary to curtail many parts of the History in the
attempt--perhaps a hopeless one--to lay before the reader in a limited
space enough about each age to illustrate its tone and spirit, the ideals
of the workers, the gradual addition of new points of view and of new
means of investigation.
It would, indeed, be a pleasure to entertain the hope that these pages
might, among new recruits, arouse an interest in the greatest of all the
sciences, or that those who have handled the theoretical or practical
side might be led by them to read in the original some of the classics of
astronomy. Many students have much compassion for the schoolboy of
to-day, who is not allowed the luxury of learning the art of reasoning
from him who still remains pre-eminently its greatest exponent, Euclid.
These students pity also the man of to-morrow, who is not to be
allowed to read, in the original Latin of the brilliant Kepler, how he
was able--by observations taken from a moving platform, the earth, of
the directions of a moving object, Mars--to deduce the exact shape of

the path of each of these planets, and their actual positions on these
paths at any time. Kepler's masterpiece is one of the most interesting
books that was ever written, combining wit, imagination, ingenuity,
and certainty.
Lastly, it must be noted that, as a History of England cannot deal with
the present Parliament, so also the unfinished researches and untested
hypotheses of many well-known astronomers of to-day cannot be
included among the records of the History of Astronomy. The writer
regrets the necessity that thus arises of leaving without mention the
names of many who are now making history in astronomical work.
G. F. _August 1st, 1909._

BOOK I. THE GEOMETRICAL PERIOD

1. PRIMITIVE ASTRONOMY AND ASTROLOGY.
The growth of intelligence in the human race has its counterpart in that
of the individual, especially in the earliest stages. Intellectual activity
and the development of reasoning powers are in both cases based upon
the accumulation of experiences, and on the comparison, classification,
arrangement, and nomenclature of these experiences. During the
infancy of each the succession of events can be watched, but there can
be no _à priori_ anticipations. Experience alone, in both cases, leads to
the idea of cause and effect as a principle that seems to dominate our
present universe, as a rule for predicting the course of events, and as a
guide to the choice of a course of action. This idea of cause and effect
is the most potent factor in developing the history of the human race, as
of the individual.
In no realm of nature is the principle of cause and effect more
conspicuous than in astronomy; and we fall into the habit of thinking of
its laws as not only being unchangeable in our universe, but necessary
to the conception of any universe that might have been substituted in its

place. The first inhabitants of the world were compelled to
accommodate their acts to the daily and annual alternations of light and
darkness and of heat and cold, as much as to the irregular changes of
weather, attacks of disease, and the fortune of war. They soon came to
regard the influence of the sun, in connection with light and heat, as a
cause. This led to a search for other signs in the heavens. If the
appearance of a comet was sometimes noted simultaneously with the
death of a great ruler, or an eclipse with a scourge of plague, these
might well be looked upon as causes in the same sense that the veering
or backing of the wind is regarded as a cause of fine or foul weather.
For these reasons we find that the earnest men of all ages have recorded
the occurrence of comets, eclipses, new stars, meteor showers, and