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.