SCIENTIFIC LITERATURE. 



707 



that, in spite of some difficulties, formal 

 logic is one of the most valuable instruments 

 in modern education for promoting clear 

 thinking and for developing critical habits 

 of mind. To doubters of the advisability 

 of attempting to include a theory of thought 

 or a philosophy of mind in an elementary 

 course in logic, Professor Creighton replies 

 that psychology having differentiated itself 

 from philosophy and become a " natural " 

 science, no longer undertakes to describe all 

 that the mind is and does. " It belongs to 

 logic to investigate intelligence as a knowing 

 function, just as it is the task of ethics to 

 deal with the practical or active mental fac- 

 ulties." Logic must first be a science before 

 it can become an art, but it can not be re- 

 garded as an art in the sense that it fur- 

 nishes a definite set of rules for thinking 

 correctly. What it can do is to show the 

 method by which new truths have been dis- 

 covered and the general conditions that must 

 always be fulfilled in reasoning correctly. 

 The treatment in the text follows the usual 

 order, except that the author, keeping clear 

 of artificial diction, writes in talking English 

 that is easy to be comprehended. 



There are no more vital problems in the 

 evolution of society than those connected 

 with the point of view, the outlook, of the 

 great masses of the " working people." 

 These people form the backbone, the poten- 

 tial energy of society ; an acquaintance with 

 their views of ethics and life, and manner of 

 living, is of the utmost importance, not only 

 per se, but especially because of the efficient 

 direction which such a knowledge can give 

 the attempts at improving these latter, and 

 through them society at large. Mr. Walter 

 Wyckoff has, apparently actuated by some 

 such view as this, in combination perhaps 

 with a desire for a novel experience, made a 

 two years' trip across the continent, living 

 chiefly among the lowest and most improvi- 

 dent class of manual laborers ; making his 

 own living by their methods, and, by means 

 of the close contact, studying them from a 

 vantage point of unusual value. The account 

 of this expedition * is, as it could not fail to 

 be, no matter who the traveler might have 



* The Workers: an Experiment in Reality. 

 The West. By Walter A. Wyckoff. New York : 

 Charles Scribner's Sons. Pp. 878. $1.50. 



been, of great interest and value. But in Mr. 

 Wyckoff's hands the story has an added at- 

 traction through the literary ability of the 

 author. There is much material of practical 

 scientific value in the volume ; it should 

 prove especially suggestive and useful to 

 some of our charity organization workers who 

 apparently find it so difficult to govern their 

 work by reason rather than emotion. There 

 are one or two rather unpleasant lapses, the 

 most marked of which advertises in a Chicago 

 police station Mr. Wyckoff's great linguistic 

 attainments, but the work is generally free 

 from this sort of weakness, and is on the 

 whole very well worth reading for instruction 

 as well as entertainment. 



The Manual of Determinative Mineralogy 

 of Professors George J. Brush and Samuel 

 L. Penficld * is intended primarily to be used 

 in the identification of minerals, and that 

 purpose has been kept prominently in view. 

 The present edition is a complete revision of 

 Professor Brush's original work, the value 

 of which and the estimation in which it is 

 held by its constituency are attested by the 

 fact that fourteen editions of it have been is- 

 sued since it first appeared in 1874. A re- 

 vision of the parts devoted to blowpipe 

 analysis and the chemical reactions of the 

 elements was published in 1896. To the 

 present edition a chapter is added on the 

 physical properties of minerals, devoted 

 chiefly to crystallography, in which the en- 

 deavor has been made to present the subject 

 as simply as possible. Importance has been 

 attached to the description of those forms 

 which are of most frequent occurrence, and 

 the examples chosen to illustrate the differ- 

 ent systems represent, as a ride, the simple 

 forms that prevail in specimens of common 

 minerals, while rare and complex forms are 

 treated very briefly. The introduction of a 

 large number of species since 18*74 has made 

 a complete rearrangement necessary in the 

 analytical tables ; aud they have been sc de- 

 veloped that tests for characteristic chemical 

 constituents furnish the chief means of iden- 

 tification. Stress is laid upon the importance 



* Manual of Determinative Mineralogy, with 

 an Introduction on Blowpipe Analysis. By George 

 J. Brush. Revised and enlarged, wita entirely 

 new tables for the identification of minerals. Fif- 

 teenth edition, first thousand. New York: John 

 Wiley & Sons, pp. 312. 



