BOOK REVIEWS. 



137 



treated. Marketing methods and fungus attacks upon plants have 

 some few pages devoted to them, but insect pests of garden plants 

 receive no special treatment. 



" The Principles of Irrigation Practice." By J. A. Widtsoe, A.M., 

 Ph.D., xxvi -f 496 pp. 8vo. (Macmillan Co., New York, 1914.) 7s. 6d. net. 



Like all the books in the " Rural Science Series," this is a first- 

 class manual of the subject with which it deals. There are vast tracts 

 of land in various parts of the world that await only a constant 

 water supply in order to render them capable of producing valuable 

 and remunerative crops. And there is need for a book bringing together 

 what has been written upon the subject, for irrigation is not a simple 

 matter of engineering to bring water from a more favoured to an arid 

 district. As with every other work of man, interference with the 

 existing order of things brings about new conditions which were not 

 apprehended at the outset, and which experience alone enables one 

 to define. With the new conditions new problems arise, and these 

 when competition becomes more keen have to be solved. All this is 

 dealt with in the present volume, and those who have to deal with 

 irrigation problems, or with irrigation practice, some of which might be 

 applied with advantage in parts of our own country, will find much 

 instruction in this well-illustrated and clearly written book and its 

 companion "Dry Farming." Probably in horticultural practice 

 sub-irrigation will be more likely to prove of value than is indicated in 

 the brief note upon it in the present volume. 



" A Manual of Weeds." By A. E. Georgia, xi + 593 pp. 8vo. 

 (Macmillan Co., New York, 1914.) 8s. 6d. net. 



Over 560 pages of this book are occupied by descriptions of weed- 

 plants, as the authoress defines them, which are apt to grow where some- 

 thing else is desired. They are the weeds in the United States, not 

 weeds of all cultivated land. The book may thus be looked upon as 

 a descriptive list of the most common American wild plants. The 

 descriptions are not too technical, each plant is illustrated by a line 

 drawing generally faithfully representing the form of the plant 

 depicted, and notes of habitat, crop liable to be infested, and range 

 and methods of control are given. A surprising number of the 

 plants referred to occur in England, while still others are welcome 

 garden plants here. 



" Inorganic Plant Poisons and Stimulants." By Dr. Winifred 

 E. Brenchley. 8vo. x + 110 pp. (University Press, Cambridge, 

 1914.) 5s. net. 



Recent research into soil problems along several lines has pointed 

 to an almost unsuspected importance attaching to the presence of 

 minute traces of certain chemical compounds in the soil. In the 

 present monograph the authoress has brought together the state- 

 ments of many writers upon the effects of inorganic substances in 



