412 



SCIENCE 



[N. S. Vol. LIII. No. 1374 



ton, $325,000; the Western at London, 

 $200,000. 



The Pennsylvania State College has re- 

 ceived from the children of the late J. Ro'b- 

 erts Lowrie the gift of his her'baritim. The 

 collection comprises 2,750 mounted varieties 

 representing 144 families and 707 genera. 



With a portion of the funds at their disposal 

 the trustees of the Captain Soott Memorial 

 Fund have decided to establish a Polar Re- 

 search Institute in connection with the new 

 department of geography in the TJniversity of 

 Cajnbridge. 



The exchange agreeanent, established before 

 the war, between Buenos Aires medical 

 schools and Paris schools, has been renewed. 

 In August of this year Professors Marcel 

 Labbe and G. Brumpt will go to Buenos Aires 

 to give lecture courses. The Buenos Aires 

 school will send to Paris either heads of clinics 

 or laboratories to take postgraduate courses in 

 Paris. 



The board of trustees of the Armour Insti- 

 tute of Technology has announced the ap- 

 pointment of Howard M. Raymond as acting 

 president of that institution to fiU temporarily 

 the vacancy caused by the recent death of Dr. 

 P. W. Gunsaulus. 



Peederick H. Sibley, formerly professor of 

 mechanical engineering at the University of 

 Kansas, has been elected dean of the college 

 of engineering at the University ofNevrda. 

 The college includes the four schools of civil, 

 electrical and meehanieal engineering and the 

 Mackay School of Mines. 



Dr. Oskar Bandisch, formerly privat-docent 

 in the University of Zurich, has accepted Ln 

 appointment as research associate in biochem- 

 istry in Yale University. Dr. Bandisch re- 

 ceived his training in organic chemistry at the 

 Technische HochschuJe in Zurich under Pro- 

 fessor Baumberger, and has contributed much 

 original work dealing with problems of plant 

 assimilation and the influence of light on 

 chemical reactions. His work at Yale wiU be 

 entirely in the graduate school. 



Dr. Shepherd I. Franz and Dr. E. A. Cut- 

 ting, respectively professor and associate pro- 



fessor of physiology at the George Washing- 

 ton University Medical School, have resigned. 



DISCUSSION AND CORRESPONDENCE 



ON THE USE OF THE TERMS "DENUDATION," 



"EROSION," "CORROSION" AND 



" CORRASION " 



In 1911 J. W. Gregory called attention to 

 the looseness with which the above terms were 

 used in geological and geographical litera- 

 ture,'^ and suggested certain restrictions in 

 their meanings. Although the confusion ia 

 the use of these terms has been generally 

 appreciated by geologists, Gregory's sugges- 

 tions have met with little favor, and no effort 

 seems to have been made to bring about a 

 uniformity of usage. In fact, a review of 

 various text-books which have appeared since 

 the publication of Gregory's article indicates 

 that the confusion is growing worse. 



Wliile the definitions suggested by Gregory 

 are open to strong objection, yet the existing 

 ambiguity in the use of such important geo- 

 logical terms can not fail to be bewildering to 

 students and authorities alike, and calls for 

 some remedial action. A few quotations 

 taken at random from recent text-books will 

 emphasize this fact. 



1. According to Tarr and Martin^ denu- 

 dation consists of weathering plus erosion, 

 and erosion is further defined as involving 

 " removal, transportation and deposition of 

 rock fragments," though on p. 115 erosion is 

 spoken of as the combined work of corrasion 

 and corrosion, no mention being made of 

 deposition. These authors apparently define 

 corrasion as the mechanical degradation of 

 rock by river water, and corrosion as the 

 chemical removal of solid rock (pp. 114, 115) 

 though the definitions are not at aU clear. 



2. Pirsson^ limits erosion to " the forma- 

 tion of rock debris and its removal " and 

 gives no definition of denudation. Corrasion 

 he defines as the action of a stream in rasping 



1 Geographical Jowrnal, Vol. 37, 1911, pp. 189- 

 195. 



2 "College Physiography," 1914, p. 18. 



3 Pirsson and Schuchert, ' ' Textbook of Geol- 

 ogy," 1915, p. 31. 



