5 6 4 



THE POPULAR SCIENCE MONTHLY. 



considered the question of how minerals 

 are combined and distributed so as to build 

 up the earth's crust ; attention is here es- 

 pecially directed to the knowledge of rock- 

 structure gained within recent years by the 

 use of the microscope. 



Part III treats in turn of the sediment- 

 ary and the eruptive rocks. Of the former, 

 the original structure, the association of 

 strata, the chronological value of strata, 

 etc., . . . are reviewed ; in connection with 

 the latter, the formation of mineral veins 

 by deposition from the molten state and 

 by deposition from water-solution is de- 

 scribed. 



Fossils, which may be termed "the 

 labels of the strata," receive the share 

 of attention due their importance, and are 

 studied as indicating former changes in ge- 

 ography, former conditions of climate, and 

 the chronological sequence of geological for- 

 mations. 



The rest of the book is given to the 

 study of the main divisions of the geologi- 

 cal record that is to say, to a systematic 

 review of the stratified formations of the 

 earth's crust. 



An appendix, furnishing an outline of 

 the classification of the vegetable and the 

 animal kingdom will prove convenient for 

 reference, and the many illustrations em- 

 bodied in the text of the volume will be a 

 welcome aid to the student. 



The "Wealth of Households. By J. T. 

 Dawson. Oxford (England): At the 

 Clarendon Press. Pp. 368. 



This is essentially a book on political 

 economy, the substance of which was first 

 put together, more than twenty years ago, 

 by way of using the experience of a man of 

 business in the education of his children. 

 It was afterward recast and delivered as 

 lectures, and then printed. Having become 

 out of print, it has been entirely rewritten, 

 as a text-book and with especial reference 

 to some of the economic questions of the 

 day. The principles of the subject, in its 

 several departments, are presented in brief, 

 pointed paragraphs, which are often short 

 enough to be maxims. Considering the 

 situation of workmen, the author deplores 

 subjection alike to capital and to the trades- 

 union ; and advises workmen to try to make 



themselves independent by getting a year's 

 subsistence ahead. This is not beyond their 

 means, for thousands of the class are daily 

 paying the price of it from means drawn 

 wholly from weekly wages. 



Manual Training. The Solution of Social 

 and Industrial Problems. By Charles 

 H. Horn. Illustrated. New York : 

 Harper & Brothers. 1886. 



The contents of this volume are briefly 

 summarized by the author as consisting, 

 first, of a detailed description of the vari- 

 ous laboratory class processes from the first 

 lesson to the last in the three years' course 

 of study at the Chicago Manual Training 

 School. The second division is " an ex- 

 haustive argument a posteriori and a for- 

 tiori in support of the proposition that 

 tool-practice is highly promotive of intel- 

 lectual growth, and in a still greater degree 

 of the up-building of character." The third 

 division deals with the history of civiliza- 

 tion as related to methods of education, and 

 in the fourth part the history of manual 

 training as an educational force is briefly 

 presented. 



Color Studies. By Thomas A. Janvier. 

 New York: Charles Scribner's Sons. 

 Pp. 227. 



A book of stories of artist-life, to which 

 an allegorical air is given by the characters 

 bearing the name of artists' colors. Accord- 

 ing to its motto, the book is without moral 

 or purpose, but " whichever way you look " 

 in it, " you'll only find a pair of lovers." 



A Popular History op Astronomy during 

 the Nineteenth Century. By Agnes 

 M. Clerke. New York : Macmillan & 

 Co. 1886. Pp. 468. Price, $4. 



" The present volume does not profess 

 to be a complete or exhaustive history of 

 astronomy during the period covered by it. 

 Its design is to present a view of the prog- 

 ress of celestial science on its most charac- 

 teristic side since the time of Herschel." 

 These words, taken from the preface, clearly 

 present the scope and aim of the book be- 

 fore us. 



The introduction refers briefly to the 

 three kinds of astronomy distinguished. 

 The first of these is known as observational 

 or practical, the second is called gravita- 



