The following lectures were really given, in substance, at a girls' school (far in the country); which, in the course of various experiments on the possibility of introducing some better practice of drawing into the modern scheme of female education, I visited frequently enough to enable the children to regard me as a friend. The Lectures always fell more or less into the form of fragmentary answers to questions; and they are allowed to retain that form, as, on the whole, likely to be more interesting than the symmetries of a continuous treatise. Many children (for the school was large) took part, at different times, in the conversations; but I have endeavored, without confusedly multiplying the number of imaginary speakers, to represent, as far as I could, the general tone of comment and inquiry among young people. [Footnote: I do not mean, in saying "imaginary," that I have not permitted to myself, in several instances, the affectionate discourtesy of some reminiscence of personal character; for which I must hope to be forgiven by my old pupils and their friends, as I could not otherwise have written the book at all. But only two sentences in all the dialogues, and the anecdote of "Dotty," are literally "historical."] It will be at once seen that these Lectures were not intended for an introduction to mineralogy. Their purpose was merely to awaken in the minds of young girls, who were ready to work earnestly and 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 A very idle talk, by the dining-room fire, after raisin-and-almond time. OLD LECTURER; FLORRIE, ISABEL, MAY, LILY, and SIBYL. OLD LECTURER (L.). Come here, Isabel, and tell me what the make- believe was, this afternoon. ISABEL (arranging herself very primly on the foot-stool). Such a dreadful one! Florrie and I were lost in the Valley of Diamonds.