328 



SCIENCE. 



[N. S. Vol. XIV. No. 348. 



clines in the new-made recent coast prairies. 

 Furthermore, these uplifts are most probably 

 due toisostatic movements rather than to accu- 

 mulations of gas. 



Another interesting fact which is developing 

 is that these oils are not associated with exten- 

 sive beds of either plant or animal remains, but 

 at one place, Saratoga, where they outcrop, 

 they apparently originate in ferruginous sands, 

 and this occurrence is strikingly suggestive of 

 Mendeleef's theory that petroleum is formed 

 by the action of warm waters on carbide of iron 

 at considerable depths. But conclusions on 

 this subject are as yet premature. 



Robert T. Hill. 



discord and beats. 



To THE Editor of Science : In a review of 

 books on physics in a recent issue of Science, I 

 find on page 259 the remark that the author 

 "has defined 'discord' more sharply than the 

 facts warrant, by failure to recognize Mayer's 

 law, which expresses the duration of the resid- 

 ual auditory sensation as a function of vibration 

 frequency, the equation being expressible in a 

 curve which Professor Mayer published in 1894 

 {Am. Jour. Set., Jan., 1894)." That authors of 

 text-books of physics discuss psychological prob- 

 lems may be very well ; for it is certainly bet- 

 ter for the student to learn some psychological 

 theories in the physical laboratory than to learn 

 them not at all. But, unfortunately, it is rare 

 to find a physicist who is sufficiently familiar 

 with the psychological literature. Permit me 

 to make these two statements : (1) That a ' dis- 

 cord ' cannot be defined by ' beats,' the psychol- 

 ogists have some time since agreed upon. The 

 physicists — on the authority of Helmholtz, 

 whose ' Tonempfindungen ' appeared 40 years 

 ago — still make use of this definition. (2) 

 Mayer's curve, as recent experiments {Zeit- 

 schrift f. Psychol, to. Physiol, cl. Sinnesorgane, 

 20 : 408-424 ; reviewed in the Psychological Re- 

 view, 7 : 88-90, 1900) prove, does not express the 

 dependency of the duration of an after-sensa- 

 tion on the frequency of vibration. The dura- 

 tion of the after-sensation does not seem to 

 depend upon the pitch at all. 



Max Meyer. 



Ukiversity of Missouei. 



the international catalogue of 

 scientific literature. 



To THE Editor of Science : Can nothing be 

 done even at this stage to secure a better sys- 

 tem of classification for the international cata- 

 logue of scientific literature now under process 

 of i)reparation under the general supervision of 

 the Royal Society in London ? In library man- 

 agement this country is, as probably every one 

 is aware, in advance of most, if not all, countries, 

 and the result of this is that the practical ap- 

 plication of the science of classification to the 

 cataloguing of books and articles has been 

 carried farther in this country than elsewhere. 

 Published systems of classification here are more 

 complete, there is a larger literature on the 

 subject, and a greater number of libraries have 

 been catalogued on a classified system. I do 

 not think anybody familiar with classification 

 and its practical application will hesitate in 

 condemning the classification which has been 

 adopted by the Royal Society. In botany, it is 

 ridiculously incomplete. It is impossible, as I 

 know from experience, to classify material on 

 this subject, in the shape of papers, without a 

 system which is at least carried down to fami- 

 lies ; and in many cases one extended to genera 

 is wise. 



The classification in geology is equally in- 

 adequate and makes insufficient- provision for 

 the great extension which has taken place in 

 physiographic geology in the last ten years. 



If any one wishes to see what can be done in 

 the line of careful classification for geological 

 purposes, M. Mourlon's ' Classified Index of 

 Geological Papers ' on the Dewey Decimal Sys- 

 tem will oflFer a striking contrast to that pre- 

 sented by the meager array of classification in 

 the Royal Society. Mnemonic aids are alto- 

 gether omitted- in this classification, no com- 

 mon system of number being used for common 

 types of classification in diflferent subjects. In 

 the biological field, no effort has been made to 

 follow a similar arrangement of homologous 

 subjects. 



In fact, I think, I speak within bounds in 

 saying that no one versed in this subject can 

 examine this classification without feeling that 

 it is prepared by some one who has neglected to 

 study what has already been done in this field. 



