704 



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 concern- 

 ing 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 ag- 

 nosticism. He does not believe that knowl- 

 edge 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 specula- 

 tion, 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 Projec- 

 tion. 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 un- 

 dergone 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 pub-^ 

 lisher, 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, be- 

 sides 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, there- 

 fore, a necessary preparation for the arti- 

 san who has to construct work from draw- 

 ings 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 includ- 

 ing all books issued from January to Au- 

 gust, inclusive, by the publishers represented 

 in the annual ; a classified summary and al- 

 phabetical 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. (foiming 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 Jer- 

 sey. 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 im- 

 mediately opposite the lower part of New 

 York City, presents many interesting fea- 

 tures, the most prominent of which is the 

 great ridge of trap-rock, forming the south- 

 ern end of the Palisades, which traverses it 

 from north to south. It is nearly perpen- 

 dicular on the eastern edge, but slopes back 

 gently toward the west. Beds of triassic 

 sandstone, slate, and shale lie on either side 

 of it. Archaean rocks gneiss in a part of 

 Jersey City, serpentine at Castle Point, Ho- 

 bqken are found within its borders. Thje 

 top of the trap ridge bears marks of the ac- 

 tion 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 de- 

 tails of these features, their relations to each 

 other, and their economical and sanitary as- 

 pects, are clearly described in the essay. 



