4 o6 SECTIONAL TRANSACTIONS.— J. 



It is suggested that during adolescence the previously prevailing tend- 

 ency undergoes modification, and extreme extroversion or introversion 

 may then be corrected. What effect has the provision of mass entertain- 

 ment on this desirable process during adolescence ? 



Afternoon. 

 Dr. B. Semeonoff. — The discrimination and estimation of loudness (2.0). 



A survey of work on the application of Weber's law to sound intensity, 

 from the earliest to the most recent investigations, shows an overwhelming 

 balance of evidence against the constancy of the ' Weber-Fechner fraction.' 

 The variation in value seems to be continuous over the intensity range. 

 Practically all investigators have found an increase in the value of the 

 difference threshold at low intensities, and a rather smaller increase has 

 often been found at high intensities. 



Fresh experiments, carried out with a 512-cycle valve-maintained tuning- 

 fork at nine intensities (roughly 25-105' db. intensity level) yielded similar 

 results. Large individual differences were found, and also considerable 

 day-to-day variation. 



The relation between stimulus and sensation may also be studied by a 

 more direct method — the estimation or judgment of loudness in absolute 

 (subjective) units. Previous investigations have usually yielded consist- 

 ency within their own bounds, but not with the results of other researches. 

 This was confirmed in a series of experiments using the above-mentioned 

 apparatus. It may be concluded that different formulations of the stimulus- 

 sensation relationship are necessary for different observers, and that these 

 functional relationships may be of fundamentally different mathematical 

 forms. 



Mr. W. F. Tyler. — A means for the comparison of hot climates (2.45). 



Our sensation reactions to climatic conditions in hot countries cannot be 

 ascertained from meteorological tabulations alone. What is needed for the 

 purpose of comparing those reactions at various places is a sensation scale 

 of degrees of climatic discomfort correlated to meteorological factors. An 

 investigation at Shanghai by the writer in 1904, conducted in natural con- 

 ditions, produced such a scale within the limits of humidity from saturation 

 to 60 per cent. 



The usual way of forming a sensation-scale from least observable differ- 

 ences was obviously impracticable, and the writer had in consequence to use 

 the method of estimates of degrees of discomfort interpolated between two 

 defined limits. As a lower limit the beginning of discomfort was satis- 

 factory, but for an upper limit an imaginary unbearable condition had, in the 

 absence of something better, to be adopted. Notwithstanding the defect of 

 that upper limit and the uncertainty regarding the ability to interpolate 

 degrees of sensation, the estimates of twelve observers over a period of a 

 month resulted quite definitely in the establishment of a relationship between 

 degrees of discomfort on the one hand, and temperature and humidity on 

 the other, with air-movement as a constant. 



This sensation scale covered — owing to the limits of the range of humidity 

 at Shanghai — only about a third of the full range of humidity. Without 

 an extension of it to the limits of aridity, a comparison of climates generally 

 cannot be effected. A further psycho-physical investigation to obtain that 



