systematically, a vital interest in the subject of their study. No
science can be learned in play; but it is often possible, in play,
to bring good fruit out of past labor, or show sufficient reasons
for the labor of the future.

The narrowness of this aim does not, indeed, justify the absence
of all reference to many important principles of structure, and
many of the most interesting orders of minerals; but I felt it
impossible to go far into detail without illustrations; and if
readers find this book useful, I may, perhaps, endeavor to
supplement it by illustrated notes of the more interesting
phenomena in separate groups of familiar minerals;--flints of the
chalk;--agates of the basalts;--and the fantastic and exquisitely
beautiful varieties of the vein-ores of the two commonest metals,
lead and iron. But I have always found that the less we speak of
our intentions, the more chance there is of our realizing them;
and this poor little book will sufficiently have done its work,
for the present, if it engages any of its young readers in study
which may enable them to despise it for its shortcomings.

DENMARK HILL: Christmas, 1865.





LECTURE 1.

THE VALLEY OF DIAMONDS