I am not aware that this reprint of some of my scattered notes and
essays demands any apology.
The practice of making such collections and selections by the author
himself has now become very general, and is much better done thus than
by friends after his death.
Besides this, it supplies a growing want of these busy times, when so
many of us are prevented by the struggles of business from sitting down
to the consecutive systematic study of a formal treatise.
I have kept this demand steadily in view throughout, by selecting
subjects which are likely to be interesting to all readers who are
sufficiently intelligent to prefer sober fact to sensational fiction,
but who, at the same time, do not profess to be scientific specialists.
In the writing of these papers my highest literary ambition has
always been to combine clearness and simplicity with some attempt at
philosophy.