714 



SCIENCE, 



[N. P, Vol. VII. No. 177. 



chology ' is unpsycliological. Psychology is not 

 primarily concerned with the time of sense, but 

 with the sense of time, that is, it is not pri- 

 marily concerned with the physical or physio- 

 logical. Hence to make memory merely some 

 simple function of time, as logarithmic, just as 

 we find gravity to vary inversely as the square 

 of the distance, is an enticing but false simpli- 

 fication of psychic act. While the physics of 

 psychology is an interesting if somewhat lim- 

 ited field, it does not deserve the term ' the 

 New Psychology.' 'The New Psychology ' is 

 that which has felt the stimulus of evolutionism, 

 and whose standpoint is not physical but bio- 

 logical. The psychic phenomenon is a life 

 method, and thus memory is a function of and 

 for life, a mode of building up experience into 

 a whole which should serve the individual and 

 race as a sort of psychic capital. 



Now the failure to take biology as the main 

 standpoint leads to the very unsatisfactory re- 

 mark (p. 208) that similarity, contrast, etc., are 

 not real laws of association in memory, but only 

 'schemes for classifying associations,' and that 

 the ' real law ' has never been found. That is, 

 we understand that some psycho-physical law 

 yet undiscovered is the real scientific explana- 

 tion, and the present psychology of memory by 

 laws of similarity, contrast, etc. , has little or no 

 value. But appreciation of likeness and same- 

 ness, for instance, is of the greatest importance 

 to the living organism, as in recognition of food, 

 mate, etc., and hence it has become a prime 

 method or law of mental organization. Mind 

 in animals and men is not a general exhibition 

 of elemental energy in space and time, but a 

 practical device for the advantage of the indi- 

 vidual and posterity ; hence the laws of associa- 

 tion, as commonly given, are vital laws and 

 real laws of connectivity in mind reaching to 

 adaptation. 



We conclude that to come to the study of 

 mind by the way of physics is to come by a back 

 door. While we should certainly try to enter 

 by every door that can be found back, side or 

 front, yet the best, most comprehensive and 

 reasonable view comes by way of the front en- 

 trance through biology. 



Hiram M. Stanley. 



Lake Foeest, III., April 25, 1898. 



THE CAUSES OF NATURAL ARCHES. 



To THE Editor of Science : The note in 

 your April 22d number regarding the natural 

 bridge in Utah is interesting, but I should like 

 to supplement it by stating another interesting 

 thing, namely, that there are in the great arid 

 region a large number of these natural arches. 

 In the Canyon of Desolation, on Green River, 

 they are particularly common, and from the 

 surface of the river some of them seemed of 

 huge proportions. All I have seen occur in 

 formations exactly similar in kind — homoge- 

 neous sandstones with tendencies toward con- 

 choidal fracture — and my observations are 

 against the wind erosion theory as a prime 

 factor. 



The beginning appears generally to be in 

 some natural crevice or cleft on the face of the 

 bare cliff wall, where water is able to penetrate 

 and allow frost to start operations by throwing 

 out a fragment that leaves a cavity almost a 

 miniature of the final perforation which marks 

 one further period in the demolition of the cliff. 

 This fragment is followed by many others, till 

 the cavity presents the appearance of an alcove 

 with arched top, and a talus floor. The arch 

 gradually deepens into the cliff, and I have seen 

 one so deep that its floor was a lake, with a 

 grove of trees at the opening. Frequently, if 

 not generally, the deepening is assisted by 

 water percolating from above. 



At a certain depth, if the cliflT is a thick one, 

 the arch begins to protect itself, and the ex- 

 cavation proceeds more slowly. It becomes a 

 cave with floors of various character according 

 to circumstances that vary with other condi- 

 tions. But if the cliff is comparatively thin the 

 wearing finally cuts through to the opposite 

 side, and then wind erosion becomes a more 

 potent factor. I have seen many examples of 

 every stage of progress, and I have seen at least 

 one beginning where a rain torrent was in ac- 

 tive operation, and made a sketch of it. Frost, 

 and the disintegrating and dissolving power of 

 water combined with structural tendencies, 

 appear therefore to be the chief causes of these 

 natural arch forms. 



F. S. Dellenbaugh. 



New York, May 3d. 



