278 REPORTS ON THE STATE OF SCIENCE, ETC. 



profitable to study what was actually ' measured ' in a number of experi- 

 ments carried out in psycho-physical research. Further, it was evident 

 that some of the experimental conditions under which these researches 

 were carried out must come under review, and that considerable light 

 would be thrown on the problem by a study of the historical order of 

 development of the subject of mental measurement. 



The Committee has been fortunate in securing the services of specialists 

 vvho have collected and discussed, in detail, the evidence for the different 

 views, and feels that it can best serve the advancement of this particular 

 branch of knowledge by putting forward the evidence for these views 

 without at present making any attempt to reconcile them. 



To this end Mr. Guild has prepared a statement of the point of view of 

 those who deny the possibility of quantitative estimates of sensory events, 

 and Prof. Drever has dealt more briefly with the question from the opposite 

 angle. Mr. Guild's statement has been circulated to the Committee, and 

 notes and criticisms received from members are included in the Report. 

 Prof. Drever, who had waited for Mr. Guild's paper before completing his 

 own work, feels that a longer time is needed for a full presentation of a 

 reply to Mr. Guild's position, but has sent in a short statement presenting 

 the case for those who give the affirmative answer to the question whether 

 sensation intensity is measurable. 



Extensive experimental work has been carried out in the Cambridge 

 Psychological Laboratory, and Mr. Craik has prepared a short summary 

 of this work, to which Prof. Bartlett has added an introductory note. 



Dr. Semeonoff, of the University of Edinburgh, has collated and studied 

 critically the immense literature connected with the subject of the measure- 

 ment of sensory magnitudes, and he has been kind enough to permit the 

 Committee to include in its Report that portion of his work which refers 

 to the measurement of sound sensation. 



For consideration of the Sections the Committee therefore present the 

 following : 



I. An historical statement by Dr. B. Semeonoff. 



II. A short summary of recent Cambridge experimental work by 

 Prof. F. C. Bartlett, F.R.S., and Mr. K. J. W. Craik, M.A. 



III. A statement by Mr. J. Guild. 



IV. Notes thereon by : ' 



A. Dr. R. H. Thouless. 



B. Dr. L. F. Richardson, F.R.S. 



C. Mr. T. Smith, F.R.S. 



D. Dr. Wm. Brown. 



E. Dr. J. H. Shaxby. 



V. A statement by Professor J. Drever. 



I. An historical statement by Dr. Semeonoff . 



The Measurement of Sound Sensation. 



Early work on the measurement of sound sensation was closely bound up 

 with tvvo other studies : (i) the search for a simple method of measuring 

 sound intensity, and (ii) the experimental verification of the validity of 

 Weber's law and its derivatives. 



Reviews of the early work on sound measurement were made in 1905 . 

 by Titchener (57), and in 1910 by Pillsbury (43). These naturally exclude 

 the recent work using electrical methods, the development of which has 

 revolutionised the whole field. A brief survey of these later methods was 



