410 SECTIONAL TRANSACTIONS.—E, F. 
variations repressed within rigid and severe limits.—The surface-cover, im- 
portant as its influence is upon the development of mineral production, exerts 
its maximum effect in the control of water-supply.—In few areas of equal 
extent is man faced more immediately and more permanently with the facts of 
geological control.—The nature and conditions of water-supply, and conse- 
quently of settlement, in Australia offer striking contrasts with those prevailing 
in such countries as Europe and Canada.—Certain features of social and political 
development consequent upon these conditions are clearly discernible. 
25. Mr. A. Srevens.—Some Rural Dwellings and Communities of 
Rural Scotland. 
The environment of the north-west of Scotland: geological; minerals and soil ; 
climatic ; vegetable. Permanent habitations in relation to form, materials, site. 
Temporary habitations: nomadism. The crofter’s industry. Site and arrangement 
of crofter villages. Conditions which determine collection of crofting communities 
into villages. 
SECTION F. 
ECONOMIC SCIENCE AND STATISTICS. 
(For references to the publication elsewhere of communications entered in the 
following list of transactions, see page 466.) 
Thursday, August 7. 
1. Presidential Address by Sir Witu1am Asuizy, Ph.D., on 
A Retrospect of Free Trade Doctrine. (Page 148.) 
2. Business Forecasting: (a) Sir Witi1aAm Brveripar, K.C.B.; 
(b) Mr. R. H. Coates. Discussion opened by Prof. H. 
MicHELL. 
Friday, August 8. 
3. Mr. G. Upyy Yutz, F.R.S.—The Population Problem from the 
Standpoint of the Pearl and Reed Law of Growth. 
The paper is largely of the nature of a review. The argument of Malthus 
shows that the population on a limited area cannot increase indefinitely in 
geometric progression, but does not suggest the true form of the law of increase. 
The ‘principles’ of Quetelet (Physique Sociale, 1835). The work of Verhulst 
(1838) and the arguments that led him to the ‘ logistic ’ formula 
L 
B—t 
ltee 
The recent (1920) independent suggestion of the same formula by Pearl and 
Reed and their work thereon. The populations of the United States, England 
and Wales, and France as illustrations. An improved method of calculating 
the constants and comparison with the method of three ordinates. Questions 
raised by the form of the curve as to the causes which determine the limit 
population, and as to the existence of an optimum population. 
oy 
4, Prof. R. M. MaclIver.—Cvwilisation and Population. 
5, Sir Wiuuiam Beveripaz, K.C.B.—The Fall of Human Fertility 
among the European Races and some of its Social Reactions. 
