F.— ECONOMICS. 129 



the summer solstice during eight days there is no change at all in 

 the length of the day as given in ' Whitaker's Almanack ' ; whereas 

 in other months there is a difference of two or three minutes from 

 day to day. A more exact illustration may be obtained from the 

 ' Nautical Almanac' There the average hourly change in the distance 

 of the sun from the celestial equator (due to his movement on the 

 celestial sphere along the ecliptic) is given from day to day. For the 

 year 1923, on June 22 the variation of the (' apparent ') Declination in 

 an hour (at noon) is given (in the volume published in 1920) as .04 ol 

 a second (angular measure), whereas on March 19 the corresponding- 

 hourly change was 69.29 seconds. Thus, considering the distance of 

 the sun from the equator (the North Declination) as the dependent 

 magnitude, dependent on the time, we find that the dependent magni- 

 tude when in the neighbourhood of its maximum varies per unit of 

 the independent variable by an amount which is 1,482 times less than 

 the variation at another date. The contrast is less striking, but still 

 marked, if we observe a neighbourhood less close to the maximum and 

 do not select the most favourable date for the purpose of comparison. 

 The change in the neighbourhood of a maximum (or minimum) would 

 often be thirty times less than the change at a distance. Similar 

 contrasts are presented by the Declination of the Moon ; for which 

 the average change per period of ten minutes is calculated for every 

 hour. With less precision than in physical science (it is not ours to 

 calculate what will happen in every ten minutes of 1923), this charac- 

 teristic property of a. maximum is fulfilled in economics. 



An illustration from the theory of monopoly is given in the 

 Economic Journal, 1908, p. 401, where the law of demand is supposed 

 (after Cournot) to be 



7/=a/(400+i/). 



9. Among the many who, following J. S. Mill {Pol. Econ. II. 

 xiv, 5), have noticed the crowding of women into comparatively few 

 occupations may be specially mentioned Mr. J. H. Jones, who con- 

 tributes the supplementary proposition that these occupations (before 

 the War) ' resembled each other far more closely than they resembled 

 the avenues which were closed to them (women) by rule or custom ' 

 (' Eeport on Women in Industiy ' [Cmd. 167], 1919, p. 182, col. 2, 

 par. 2). Query whether much importance now attaches to the supple- 

 mentary proposition submitted by Leroy-Beaulieu (' Lei travail des 

 femmes ... ' P'. 136) that the specially feminine occupations do not 

 admit of much division of labour or frequent intervention of mechanism ? 



10. The grounds of the assertion that the equilibrium of the labour 

 market is apt to be, even theor-etically, somewhat indeterminate are ta 

 be sought in the writer's essay on ^Mathematical Psychics.' We niay 

 begin by considering two extreme abstract cases : (1) a market consisting 

 of an equal number of masters and men ; subject to the conditions (a) 

 that no man can (or at least does) serve two' masters simultaneously, 

 (P) no master employs more than one man; (2) a market in which 

 the number of masters (though absolutely large, and so favourable to 

 competition) is small relatively to the number of men; sul)ject to con- 



l2 



