The _Natural Advanced Geography_[60] is a successful application of modern methods to the teaching of this science, and presents it with the interest undiminished which really appertains to it. While in the elementary book of this, the "natural" series, the pupil starts from his own home and is introduced to the study of man in relation to his environment, in the present work the fact is developed that environment itself is the chief factor in the various activities and economies of man. One of the salient features of the presentation of the subject, marked throughout the work, and one that commands high praise, is the arrangement of the facts into such order that their correlation may be perceived and the unity of Nature recognized. The isolated, barren, curt, unrelated statements that made the study of many of the old geographies hard and tedious are conspicuously absent, and the subject, studied in orderly sequence, "unfolds itself naturally and logically, each lesson preparing the way for those which follow." The first part of the work is devoted to a study of the world as a whole. The second part, comprising about three fourths of the volume, is an application of these laws to the various countries of the globe, beginning with the United States. In the United States, for instance, a general description of the whole is given, which presents a real, comprehensive mental picture of the country; and the process is repeated, in measure according to the conditions, for the several States, so that the pupil is taught what are the factors that give the characteristics and local features to each. A like method is pursued, on a more general scale, with other countries. The colored maps are drawn on a system of uniform scales, with reliefs plainly shown according to the accepted conventions; graphic charts or sketch maps showing the distribution of products and resources are employed; and pedagogical exercises and aids are afforded abundantly. A text-book on the _Differential and Integral Calculus_,[61] for students who have a working knowledge of elementary geometry, algebra, trigonometry, and analytical geometry, by Prof. _P. A. Lambert_, has the threefold object of inspiring confidence, by a logical presentation of principles, in the methods of infinitesimal analysis; of aiding, through numerous problems, in acquiring facility in the use of these methods; and, by applications to problems in physics, engineering, and other branches of mathematics, to show the practical value of the calculus. By a division of the matter according to classes of functions, it is made possible to introduce these applications from the start, and thereby to arouse the interest of the student. By simultaneous treatment of differentiation and integration and the use of trigonometric substitution to simplify integration it is sought to economize the time and effort of the student.