708 



THE POPULAR SCIENCE MONTHLY. 



science, and who desire to know more. Curi- 

 osity and culture are in effect convertible 

 terms : the wish to know is the first condi- 

 tion of knowing. To many who are in this 

 stage of culture, but who have neither the 

 time nor faculty for following up closely the 

 ever-widening circle of advanced thought, it 

 may be interesting to get some general and 

 popular idea of some of the unsolved prob- 

 lems which have been raised by modern sci- 

 ence, and are occupying the thoughts of the 

 men who lead its van." To meet the want 

 defined in this passage is the object of the 

 present volume. The questions which the 

 author discusses in his earlier chapters re- 

 late to the past history of the earth and 

 other cosmic bodies. These are, How long 

 has the sun been giving out heat enough to 

 sustain life on the earth ? What is the uni- 

 verse made of ? What has been the climate 

 of the earth in geologic times ? When was 

 the Glacial period, and how long did it last ? 

 From these topics he passes to the consider- 

 ation of the antiquity of man and the method 

 of his origin. A chapter is devoted to " Ani- 

 mal Magnetism and Spiritualism " ; several 

 religious questions are then taken up ; and, 

 finally, certain economic problems are con- 

 sidered. The religious questions are, whether 

 agnosticism is reconcilable with Christianity ; 

 how great a historical element there is in the 

 Gospels ; and whether the skepticism of the 

 present day justifies pessimism. " The Creeds 

 of Great Poets " are also passed in review. 

 First of the political and economic essays is 

 an analysis of the reasons for the tension 

 which keeps Europe constantly armed ; the 

 others deal with the financial problems of 

 England, and the increase of population with 

 reference to the food-supply of the world. 

 In the case of each problem which he raises, 

 Mr. Laing makes evident what solution he 

 deems most probable. His discussions show 

 a thorough knowledge of and sympathy with 

 the scientific enlightenment of the times ; 

 and, in regard to those questions which man 

 must answer in the future, he is generally 

 confident that science will be able to give a 

 beneficent solution. The only exception is 

 in regard to the food problem, where he 

 can see relief only from a diminished birth- 

 rate or an increased death-rate, and the idea 

 of discovering new ways of producing edible 

 products is not mentioned. 



Timber and some of its Diseases. By H. 

 Marshall Ward. London and New 

 York : Macmillan & Co. Pp. 295. Price, 



$1.15. 



This work originated in a series of short 

 articles in " Nature," and forms one of the 

 Messrs. Macmillan's "Nature Series." It is 

 intended as a popular scientific rather than 

 an exhaustive and technical account of its 

 subject. The opening chapters deal with 

 the general character and structure and the 

 properties and varieties of timbers ; also with 

 the classification of timbers based on these 

 properties. An extended review of the the- 

 ories about the ascent of water in tall trees 

 is given, the conclusion of the author being 

 that of the imbibition theory of Sachs and 

 the osmosis-gas-pressure theory of Hartig and 

 Godlewski and others, the latter is the more 

 probable. While he admits that the rhyth- 

 mical character of the respiration of proto- 

 plasm, on which the osmosis-pressure theory 

 depends, is not proved, he maintains that re- 

 cent researches are in favor of Godlewski's 

 views as to the behavior of the protoplasm. 

 The next three chapters deal with the dry- 

 rot and other diseases of timber caused by 

 various fungi, figures of which are given. 

 The structure of the bark of trees, and the 

 process of healing wounds by occlusion, are 

 then described, with illustrations. Returning 

 to diseases, the author describes " canker," 

 or the larch disease, leaf diseases, and pine 

 blister. The final chapter deals with the 

 " damping off " of seedling trees. 



Institutes of Economics. By E. B. An- 

 drews, D. D., LL. D., President of Brown 

 University. Boston: Silver, Burdett & 

 Co. Pp. 227. Price, $1.30. 

 The most conspicuous feature of this 

 book is the thoroughness with which its con- 

 tents has been analyzed, classified, and an- 

 notated. It is introduced by a chapter de- 

 fining the field of economics and stating 

 the nature of the chief schools of econo- 

 mists. The body of the work is divided into 

 six parts, devoted respectively to production, 

 exchange, money and credit, distribution, 

 consumption, and " practical topics involving 

 economic theory," which last includes chap- 

 ters on coin and paper currency in the United 

 States, taxation, and poverty. It is an ele- 

 mentary text-book, intended for classes in 

 colleges and, with perhaps the omission of 



