166 



SCIENCE 



[N. S. Vol. XLV. No. 1155 



It may be accepted as a fact that, unless dredg- 

 ing is supplemented by preventive measures, slides 

 mU continue to fill the Canal prism at intervals 

 for an indefinite period, that traffic through the 

 Canal will be interrupted for weeks and months at 

 a time and that the expense of removing the slide 

 material vriU add millions to the investment. As a 

 commercial undertaking the Canal will be a flat 

 failure unless continuous traffic through the water- 

 way can be guaranteed; if extensive delays due to 

 slides occur every fall when the effect of the sum- 

 mer deluge is felt, schedules, rates and contracts 

 will be disturbed so frequently that fifty per cent. 

 of the Canal's usefulness will be gone, even if the 

 closed season lasts for only a few weeks at a time. 



Aside from its commercial aspect, the Panama 

 Canal was designed to be one of the country 's most 

 important defensive works. A continuation of the 

 slides at frequent intervals will render the ditch 

 worthless as a defense measure. . . . 



Half a canal is worse than no canal. MufBed 

 exclamations of admiration will not stop the slides. 

 Unless the slides are stopped, definitely and per- 

 manently, the Canal is a failure as a commercial 

 undertaking and a defense measure. Dredging the 

 debris -will not stop the slides.i 



iNeitlier Dr. Branner, the writer, nor any 

 other patriotic citizen would intentionally cir- 

 culate false reports in regard to existing con- 

 ditions in the Panama Canal region nor ven- 

 ture to make predictions that might unduly 

 alarm the public, but, on the other hand, 

 nothing is gained by fostering a false sense 

 of security. 



In England, Germany and Russia reports 

 of the failure of the canal are said to have 

 been freely circulated. These reports have 

 emanated from geologists and engineers and 

 seem to have led many of the people in those 

 countries to believe that the Panama Canal 

 would eventually be abandoned and the Nica- 

 ragua route substituted. These reports either 

 exaggerate the importance of the slides or 

 underestimate the will of the people of this 

 country. If the earthquake menace, to which 

 Dr. Branner calls attention in his article in 

 Sunset, does not materialize, the Panama 

 Canal will unquestionably be completed and 

 made to serve its intended purpose, even 



1 Editorial in Sunset, the Pacific Monthly, June, 

 1916, p. 35. 



though it require years of time and the expen- 

 diture of additional millions of dollars to ac- 

 complish. The American people would not 

 willingly abandon a project that has so stirred 

 the pride and stimulated the patriotism of the 

 entire country as has the Panama Canal, even 

 though the length of time for its completion 

 and its cost far exceed the early calculations. 

 Benj. L. Miller 

 Lehigh Universitt, 

 December 12, 1916 



SCIENTIFIC BOOKS 



Field Geology. By Frederick H. Lahee, 

 Assistant Professor of Geology in the Massa- 

 chusetts Institute of Technology. McGraw 

 Hill Book Co., 1916. 



The title of this book suggests two possible 

 ways in which it may be used; as a prepara- 

 tion for field work, and a hand-book in the 

 field. It is for the latter use, as a reference 

 book in the field, that it will be found to be 

 especially valuable. 



The plan of the author is an unusual and, 

 in the reviewer's opinion, a very desirable 

 one. " Where possible the treatment has been 

 empirical rather than genetic." Two examples 

 will illustrate this method of presentation. 

 Under Hills, Ridges and Other Positive Land 

 Forms are included (1) Fault Mountains, (2) 

 Volcanic Cones, (3) Constructional Hills and 

 Ridges, such as sand dunes, drumlins, eskers, 

 kames, moraines and winter talus ridges. 

 Under Cross-bedding are included (1) Delta 

 Structure, (2) Torrential Cross-bedding, (3) 

 Wave-built Cross-bedding, (4) Eolian Cross- 

 bedding, and (5) Ripple marks. In other 

 words, forms which look alike are classed to- 

 gether without regard to their origin. 



A number of tables for the identification 

 of structures and topographic forms are scat- 

 tered through the text and included in the 

 appendix. These analyses have been prepared 

 with almost as much care and detail as are 

 those in botanies for the identification of 

 flowering plants. Especially is this true of 

 the table of clastic sedimentary rocks (pp. 

 463-471). It is doubtful, however, if these 

 tables will prove of great value in the field as 



