September 7, 1900. ] 



SCIENCE. 



375 



of perspective in a picture. But the pretended 

 views of Pig. 91 are not views at all but maps 

 differently colored. The Nova Scotia St. Law- 

 rence view for instance shows no foi'eshortening 

 with distances, but the same defect is present 

 in the first sketch. It is an attempt to teach 

 by trickery ; for being false maps they cannot 

 convey the idea of what a map really is. 



Now that the objections have been stated let 

 me hasten to express a hope that the small size 

 geography has come to stay. 



The maps of North America, Fig. 123, and the 

 New England States, Fig. 125, seem to me very 

 beautiful maps, but will Brockton and Haverhill 

 agree that Plymouth is more important in New 

 England geography than they ? The make-up 

 of the book is attractive, but it should be much 

 revised before being offered to the schools. 



The good features of the volume are devel- 

 oped in the admirable Second Book, ' North 

 America.' After occupying a quarter of their 

 space with a hastily written account of gen- 

 eral physical geography, the authors present a 

 splendid picture of the varied life and indus- 

 tries of different parts of this country, profusely 

 illustrated. This portion of the book is admir- 

 able. Where older or briefer books have con- 

 tented themselves with stating occupations and 

 products, Tarr and McMurray describe industries 

 so vividly and realistically that the interest is 

 absorbing. Professor Tarr's books make ' easy 

 reading,' and this one is no exception. It is 

 to be hoped the use of the volume will be wide- 

 spread. The teacher's part will be easy. His- 

 tory and industry are both referred to a geo- 

 graphic basis. 



Each volume is closed by statistical tables 

 and a pronouncing vocabulary. The latter 

 would be more valuable did it not attempt a 

 closeness of sound reproduction that demands 

 special knowledge of languages and sounds for 

 proper handling. Some inconsistencies and 

 mispronunciatioHS result. Accent and sounds 

 of Spanish words need special revision. Tus- 

 con for Tucson is the only misprint noted in the 

 two volumes though a number of errors in the 

 pronunciation are very likely chargeable to the 

 printer. The maps are admirable apart from 

 the hemispheres and Mercator repeated from the 

 First Book. Mark S. W. Jefferson. 



Wireless Telegraphy and Hertzian Waves. By 



S. R. BoTTONE. Whittaker & Co., London. 



Cloth. Pp. 116. 35 illustrations. 



This little book contains a brief account of 

 the phenomena of Hertzian waves and of the de- 

 velopment of the system of transmitting sig- 

 nals known as wireless telegraphy. The first 

 chapter is intended for readers who are not 

 familiar with even the more elementary ideas 

 concerning electrical phenomena. The second 

 chapter gives a brief account of the historical 

 development of wireless telegraphy, and the 

 next chapter on Hertzian waves describes in a 

 very simple manner the methods of generating 

 these waves and some of the methods of detect- 

 ing them, especially those employing the co- 

 herer. The chapter on constructional details, 

 which comprises nearly half the book, contains 

 directions for making in an inexpensive way 

 the apparatus required for experiments in the 

 field of wireless telegraphy. 



The comparison which the author makes be- 

 tween the action of a coherer and the action of 

 iron filings in a helix through which an electri- 

 cal current is passing is rather a misleading 

 one, and the impression is given that it is nec- 

 essary to have the coherer circuit carefully 

 tuned to the transmitting circuit in order to 

 have the coherer respond. Otherwise for a 

 simple presentation of so difficult a subject the 

 book contains very few misleading statements. 



F. L. T. 



SCIENTIFIC JOURNALS AND ARTICLES. 



In the September number of The American 

 Journal of Physiology J. Van Denburgh and O. 

 B. Wright present a carefully prepared account 

 of their experiments ' On the physiological ac- 

 tion of the poisonous secretion of the Gila 

 Monster [Heloderma suspectum).'' They find 

 that the poison is essentially like the various 

 snake venoms in its effects. The rate of respi- 

 ration, the activity of the heart, the irritability 

 of the sensory apparatus, the rapidity of coagu- 

 lation of the blood, all suffer first an increase, 

 and later a retardation with a gradual total 

 loss of function. This primary quickening and 

 secondary paralysis is not seen in the vaso- 

 motor center ; instead, the poison causes im- 

 mediately a great fall in blood pressure due to 



