272 The Plant World. 



The results presented in the table give clear evidence on the 

 im.portance of the rain error in the operation of the ordinary 

 porous cup atmometer. While the general relation of the two 

 evaporations rates in the two Cinchona habitats would appear 

 approximately the same from the readings of either instrument, 

 vet the num.erical relations of this factor in two such habitats 

 m.ust approach the truth m.uch more nearly when the non-rain- 

 absorbing instrument is used. These results, which embody the 

 first test of the new instrument in habitat study, are strongly in 

 favor of its general use. 



The writer wishes to express his thanks to Prof. B. E. Living- 

 ston for assistance and advice in the preparation of the instru- 

 ments and otherwise, and to Mr. L. W. Sharp, for his kindness in 

 attending to the apparatus during the latter portion of the period 

 of observation. 



The Desert Laboratory, 

 Tticson, Arizona. 



A BOOK FOR TEACHERS OF BOTANY. * 

 By G. J. Peirce. 



This book appears, virtually re-written, in a second edition. 

 In paper, binding and letter-press it conforms to the standard 

 of the publishers. In contents it is unusual. 



Professors of botany in American colleges may be divided 

 into two classes, teaching botanists and botanists who do more 

 or less teaching. Of the former class I believe there are com- 

 paratively few, of the latter, many. A "Professor of Educa- 

 tion " is alleged to have said that he had finally become convinced 

 that it was advisable for a person to know something of the sub- 

 feet which he or she taught, in addition to knowing the methods 

 of teaching. This remark, whether or not correctly attributed 

 to a "Professor of Education," is scarcely more preposterous 

 than the practice of many of us of doing the best we can with 

 some knowledge of our subject and only inspiration as to the 

 methods of teaching it. Most of us give little or no attention to 

 the topics especially treated in this book, trusting to the interest 



•The Teaching Botanist. By W. F. Ganong. Professor of Botany in Smith College. (The 

 Macmillan Company, New York, 1910. $1.25 net.) 



