Chemistry and Physics. 91 



powdered and closely packed in a glass tube. Particular atten- 

 tion was devoted to different varieties of mica, tourmaline, and 

 some of the aluminum alloys. — Proc. Roy. Soc. London, 96, 429, 

 1920. F. E. B. 



9. The Airplane; by Frederick Bedell. Pp. VIII, 257. 

 New York, 1920 (D. Van Nostrand Company; $3.00 net).— 

 This volume is a development from the author's experience in 

 preparing courses for Schools of Military Aeronautics, and is 

 in fact an extension of his previous works entitled Airplane 

 Characteristics, and The Air Propeller. It may be described as 

 a reasonably complete text of airplane performance, with suf- 

 ficient theory to guide the experimenter and designer and to pro- 

 vide the general reader, whose aim is educational or scientific, 

 with an accurate statement of how sustentation and stability of 

 flight are secured. 



The mathematics of the book does not go beyond the simple 

 algebraic equations of mechanics which involve the forces of 

 weight and fluid resistance, restoring couples, and applied power. 

 The complex and more or less obscure relations between the vari- 

 ables, or their dependence upon empirical constants (parameters) 

 are clearly illustrated by a large number of diagrams. 



Six of the chapters, which treat of, sustentation, wing and 

 parasite resistance, thrust and power, have been previously pub- 

 lished in the books above named. The seven new chapters dis- 

 cuss the more general topics of airplane performance at different 

 altitudes, longitudinal, lateral, and directional stability, climb- 

 ing, gliding, and structural features connected with the number 

 of planes, the keel, the rudder, and the controls. 



Among the men in this country who have attempted to de- 

 velop the physical principles involved in flying and sought to 

 codify them for the benefit of science Professor Bedell holds a 

 prominent place, and his success in presenting them will be 

 recognized by the reader of this book. It is provided with a 

 glossary of the terminology of aviation and an excellent index but 

 the draughtsmanship and reproduction of the figures is unworthy 

 of the publishers. A conspicuous lack is the absence of any 

 reference to the literature of aviation either American or for- 

 eign. F. E. B. 



10. A Field and Laboratory Guide in Physical Natter e Study; 

 by Elliot R. Downing. Pp. 109. Chicago, 1920 (University of 

 Chicago Press). — This is a loose leaf text- and note-book for use 

 in teacher training classes and normal schools. Its aim is to 

 bring the pupil into contact with elementary scientific facts and 

 phenomena and present them in such form that they will suggest 

 problems inviting further study. One chapter treats of common 

 rocks and minerals and their classification into various categories. 

 Another suggests simple and interesting observations to be made 

 upon the constellations or the sun and moon. The nine remain- 

 ing chapters of the work are devoted to the construction of vari- 



