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these conclusions are based are almost wholly arbitrary, and totally uncon- 

 vincing. In some cases it amounts to little more than drawing straight lines 

 connecting two or more places from which one or more earthquakes have been 

 reported. It is to be regretted that so much stress has been placed upon such 

 doubtful cases, for it is liable to discredit the whole theory, by attracting attention 

 to the weak parts and thereby throwing doubts even on the strong parts. 



Following these chapters are four in which are presented summary statements 

 of phenomena associated with notable earthquakes in North America and other 

 parts of the world; and this is followed by a chapter on earthquake danger spots 

 within the United States. It is to be hoped that the intimation that the large 

 coastal cities, from Washington to Boston, are on a danger line will not be verified 

 by future earthquake phenomena. 



The next chapter deals rather fully with the sounds, or hrontidi, accompanying 

 earthquakes, and a discussion of the significance of noises from the earth when 

 there are no sensible shocks. Then comes a chapter on the "Study of Earth- 

 quakes on the Ground," in which there are some suggestions that will doubtless 

 be of decided value to amateur observers, as well as to others, who have the 

 opportunity of studying an earthquake and its results. The last four chapters 

 deal respectively with disturbances in the ocean, seismographs, interpretation 

 of seismograph records, and disturbances of gravity and earth magnetism. In the 

 last two chapters the importance of distant seismographic records is clearly 

 shown, and the main results so far attained are stated. 



Each of the chapters is closed with a selected series of references to original 

 papers, which will be of use to those who wish to pursue the subject further. 

 The book is well printed and adequately illustrated with one hundred and twelve 

 figures and maps, and twenty-four pages of half tone plates, on most of which 

 there are two pictures. 



To prepare a general summary of a large subject, in the compass of a little 

 over three hundred pages, and to present the matter clearly and scientifically, 

 and yet in such a manner as to interest both the lay reader and the student of 

 science, is one of the most difficult forms of writing, and the author of this book 

 is to be congratulated on the success which he has attained in his effort to accom- 

 plish this end. He has given us a readable book, and yet one in which even the 

 geologist will find new matter, unless he has followed all the latest literature on 

 the subject of earthquakes from the standpoint of both the physicist and the 

 geologist. The student of geology, as well as the layman, will find the book 

 interesting, suggestive, and informing. It takes rank with the best of the general 



books on seismology. 



Ralph S. Tare 



The Iron Ores of the Salisbury District of Connecticut, New York, and 

 Massachusetts. By William Herbert Hobbs. (Reprint from 

 Economic Geology, Vol. II, No. 2, March- April, 1907, pp. 153-81.) 



From the low-grade limonite ore of this district a superior grade of 



