Tun present is, emphatically, an age of utility. However profound and accurate a book may be, its career will be brief and its circulation limited, unless it is eminently practical, and wisely adapted to its pur pose. Hence it often happens, that persons of undoubted abilities as men of learning, have utterly failed in their attempts to produce avail able text-books in their respective departments of study. Experience as a teacher, and tact as a compiler, are as important to the author of a school-book, as a knowledge of the subject upon which he writes. And even with all these endowments, few writers of elementary works are satisfied with their own productions till actual use in the school-room has shown wherein they are defective, or want ing in adaptation, and of what improvements they are capable. Hence almost every new school-book is revised and improved, before it passes to a second edition.