of no different order from
that which is employed in the affairs of everyday life. The science of
mathematics is perhaps responsible for the idea that some kind of
difference does exist; but mathematical processes are, in effect, no
more than ordinary logic in concentrated form, the _shorthand of
reasoning_, so to speak. I have attempted in the following pages to take
the main facts and theories of Astronomy out of those mathematical forms
which repel the general reader, and to present them in the _ordinary
language of our workaday world_.

The few diagrams introduced are altogether supplementary, and are not
connected with the text by any wearying cross-references. Each diagram
is complete in itself, being intended to serve as a pictorial aid, in
case the wording of the text should not have perfectly conveyed the
desired meaning. The full page illustrations are also described as
adequately as possible at the foot of each.

As to the coloured frontispiece, this must be placed in a category by
itself. It is the work of the _artist_ as distinct from the scientist.

The book itself contains incidentally a good deal of matter concerned
with the Astronomy of the past, the introduction of which has been found
necessary in order to make clearer the Astronomy of our time.

It would be quite impossible for me to enumerate here the many sources
from which information has been drawn. But I acknowledge my especial
indebtedness to Professor F.R. Moulton's _Introduction to Astronomy_
(Macmillan, 1906), to the works on Eclipses of the late Rev. S.J.
Johnson and of Mr. W.T. Lynn, and to the excellent _Journals of the
British Astronomical Association_. Further, for those grand questions
concerned with the Stellar Universe at large, I owe a very deep debt to
the writings of the famous American astronomer, Professor Simon Newcomb,
and of our own countryman, Mr. John Ellard Gore; to the latter of whom I
am under an additional obligation for much valuable information
privately rendered.

In my search for suitable illustrations, I have been greatly aided by
the kindly advice of Mr. W. H. Wesley, the Assistant Secretary of the
Royal Astronomical Society. To those who have been so good as to permit
me to reproduce pictures and photographs, I desire to record my best
thanks as follows:--To the French Artist, Mdlle. Andree Moch; to the
Astronomer Royal; to Sir David Gill, K.C.B., LL.D., F.R.S.; to the
Council of the Royal Astronomical Soci