SCIENCE 



Friday, Februaet 10, 1911 



CONTENTS 



The American Association for the Advance- 

 ment of Science: — 

 The Relations of Isosta-sy to Geodesy, Geo- 

 physics and Geology: Dr. John F. Hayfobd 199 



The Mershon Expedition to the Chanty 

 Islands, Lake Ewron: Dr. Alexandeb G. 

 KUTHVEN 208 



Artesian Wells of Argentina 209 



The Engineering Building of the University 

 of Cindtinati 210 



The International School of American Arche- 

 ology and Ethnology 211 



Scientific Notes and News 211 



University and Educational A ews 215 



Discussion and Correspondence: — 



University Fellowships: Professor S. N. 

 Patten, President David fSTARB Jordan. 

 The Arizona Passenger Pigeons: Dr. J. A. 

 Allen. The Transference of Names in 

 Zoology: W. T. Calman 216 



Scientific Books: — 



Eltringham's African Mimetic Butterflies: 

 Professor T. D. A. Cockerell. Kinnicutt's 

 Sewage Disposal: De. George W. Fuller. 

 Eneass on the Practise and Theory of the 

 Injector: Professor E. M. Goss 219 



Soil Productivity: Professor T. C. Cham- 

 BERLIN 225 



Notes on Meteorology a/nd Climatology: 

 Andrew H. Palmer 227 



Special Articles: — 



Cereal Cropping Methods after Soil Steril- 

 ization: Professor H. L. Bolley. Ter- 

 tiary Deposits of Northeastern Mexico: 

 E. T. Dumble 2-29 



Societies and Academies : — 



The American Philosophical Society. The 

 Philosophical Society of Washington: R. 

 L. Faeis 234 



MSS. intended for publication and books, etc.. Intended for 

 review should be seut to the Editor of Science, Garrison-on- 

 Hudson. N, Y. 



THE AMERICAN ASSOCIATION FOR THE 

 ADVANCEMENT OF SCIENCE 

 ''the RELATIONS OF I808TAST TO GEOD- 

 ESY, GEOPHYSICS AND GEOLOGY^ 



Within the past ten years geodetic ob- 

 servations have furnished positive proof 

 that a close approximation to the condition 

 called isostasy exists in the earth and com- 

 paratively near its surface. 



Let the depth within which isostasy is 

 found be called the depth of compensation. 

 Think of a prismatic column which has 

 for its base a unit area of the horizontal 

 surface which lies at the depth of compen- 

 sation, which has for its edges vertical 

 lines, and has for its upper limit the actual 

 irregular surface of the earth (or the sea 

 surface if the upper end of the column is 

 in the ocean). The condition called isos- 

 tasy is defined by saying that the masses in 

 all such columns are equal. 



Fig. 1 (p. 202) represents two such 

 columns. Column A is under the land and 

 column B is adjacent to it under the ocean. 

 If the condition called isostasy exists in two 

 such columns having equal bases they have 

 equal masses. Note that if this is true the 

 average density in column A must be less 

 than the average density in column B, for 

 the volume of column A is greater than 

 that of column B. This may be partially 

 expressed by the statement that each excess 

 of mass represented by material lying 

 above sea level is compensated for by a 



^ Address of retiring vice-president of Section 

 D (Mechanical Science and Engineering) of the 

 American Association for the Advancement of 

 Science, at Minneapolis, December 29, 1910, by- 

 John F. Hayford, director. College of Engineer- 

 ing, Northwestern University, Evanston, 111. 



