THE POPULAR SCIENCE MONTHLY.
study rather than a substitute for it. There is a considerable biographical clement in the treatment, and the author's aim seems to be to elaborate "correct views concerning the essential nature and value of the most conspicuous current of abstract thought in the English language." The author is a metaphysician and an ontologist, and, in so far as his work is doctrinal, it is a dry agnosticism. He does not believe that knowledge is bounded by phenomenal relations, and spurns the idea that any amount of generalized truth derived from the sciences can form a system of philosophy properly so called; but, independent of its speculation, there is much instruction to be gained from his work.
Elementary Projection-Drawing. By D. Edward Warren, C. E. New York: John Wiley & Sons. 1880. Pp. 162. Price, $1.50.
Practical Plane Geometry and Projection. 2 vols. By Henry Angel. New York: G. P. Putnam's Sons. 1880. Price, $3.50.
The first of these text-books is the well-known manual of Professor Warren, which has now reached a fifth edition. It has undergone a thorough revision, and some parts of it have been rewritten, while it has been made more complete by the addition of a division devoted to a consideration of the elements of machines.
The work of Professor Angel is one in the "Advanced Science Series" of the publisher, and forms a continuation of the more elementary one of the author in the same series. The chapters upon projection are prefaced by several upon plane geometry, while the main subject is fully presented and illustrated by numerous examples and problems. A volume of finely executed plates accompanies the text.
The subject of projection-drawing, besides being of large educational value, is also of great practical importance. It is concerned with representing upon a plane surface solid objects in such a way as to show their real dimensions, and is, therefore, a necessary preparation for the artisan who has to construct work from drawings of this kind. It is also of value to all those who desire to know how to represent their ideas of any construction, so that they will be understood by mechanics. Any one desiring to pursue the study will find in either of these works all that he needs to a thorough comprehension of it.
The Publishers' Trade-List Annual, 1880. Eighth Year. New York: F. Leypoldt. Price, $1.50.
This massive volume embraces the latest catalogues of their books supplied by the publishers, preceded by an order list including all books issued from January to August, inclusive, by the publishers represented in the annual; a classified summary and alphabetical reference list of books recorded in the "Publishers' Weekly" from July 1, 1879, to June 30, 1880, with additional titles, corrections, changes of price and publisher, etc. (forming a provisional supplement to the American Catalogue); and the American Educational Catalogue for 1880. The work, the materials of which are received directly from the publishers themselves, gives the complete literary history of the year in the United States, and is indispensable to the book-buyer.
The Geology of Hudson County, New Jersey. By Israel C. Russell. (From the Annals of the New York Academy of Sciences.) Pp. 80, with Two Plates.
The geology of this county, which is immediately opposite the lower part of New York City, presents many interesting features, the most prominent of which is the great ridge of trap-rock, forming the southern end of the Palisades, which traverses it from north to south. It is nearly perpendicular on the eastern edge, but slopes back gently toward the west. Beds of triassic sandstone, slate, and shale lie on either side of it. Archæan—rocks gneiss in a part of Jersey City, serpentine at Castle Point, Hoboken—are found within its borders. The top of the trap ridge bears marks of the action of the great glacier, whose moraine is found on Long and Staten Islands and in the "Short Hills" of Plainfield. On the surface are sand-dunes along the Newark meadows and Newark Bay, and on Bergen Neck, and the swamp deposits of the salt meadows, still in process of accumulation. The details of these features, their relations to each other, and their economical and sanitary aspects, are clearly described in the essay.