TESTIMONIALE

also done their part well. It is a luxury to sweep the hand over thèse smooth, solid, glossy pages, — beautiful also to the eye, in their oldstyle type and in their wealth of scientific illustration, — and think of the books as specially designed for our Common Schools."

The San Francisco Bulletin, (March 20, 1869,) in a review of the whole séries, says : " Thèse works embody the latest results of scientific discovery. The compilers wisely discard theory, however plausible and fascinating, unless it rests on a solid groundwork of truth. The arrangement and divisions of subjects are judicious ; the method of teaching is based on correct principles. The définitions are clear and concise ; the notes are models of perspicuity. There is no useless verbiage ; no vague generalization ; no rhapsodies of style. The student is directly introduced to the subject, and kept rigidly to it until he has mastered it. At the close of each section the ground gone over is revievved, and the principles educed are summed up in a few pithy axioms. While thèse volumes are more immediately designed for the use of schools, they have high, claims to récognition as scientific treatises. We can hardly think of any other source where so much valuable knowledge of physics can be found in so short a compass. The subjects are discussed with a freshness and oftentimes a grasp of thought rare in books of the kind."

The Boston Courier says of the whole séries : n They are in advance, by a great stride, of other text-books in common use, not only because they pursue the only rational method, so long ago înstituted by Bacon, and yet so much neglected, of deducing principles from facts, instead of supporting rules laid dovvn by examples, but also because they have kept pace with the progress of constantly accumulating knowledge and furnish us with the iatest results. They are Model Books."

The Boston Daily Aa1ve?'tiser says : It is in their attempt to keep up with the progress and présent condition of scientific knowledge, that thèse volumes differ most widely from the text-books gênerai ly used in our schools. Chemistry and electricity — heat, light, and sound — wear, :n this Cambridge Course of Physics, a very différent aspect from that which they présent in similar treatises of flve-and-