256 
Age at Marriage and Deration of Life 
it can be seriously held that there has been very much Malthusian restraint; 
especially is this so when it is borne in mind that the potential embryonic life has 
not of course been taken into account. It may therefore I think be held that the 
distributions of fertility as set forth in Tables XV. and XVI. are as nearly as 
possible those of a non-restricting population. 
G. On the Correlation between Age at Marriage and Duration of Life 
beyond Age 46. 
Although in Section A of this investigation we found that the number of 
offspring born to a woman is highly correlated with the duration of life beyond 
the repi'oductive period, irrespective of the age at marriage, yet it is possible 
that the fact that maximum fertility is not favourable to extreme longevity may 
be due to the generally early contraction of marriages, which is of course generally 
productive of large families — before the proper development of the reproductive 
organs. The period of mature or maximum development has been shown else- 
where to be about age 25*. Although it is clear that early marriage has not the 
effect of arresting development (perhaps it tends to too rapid development), this 
may be accomplished to the subsequent prejudice of life. Had it been possible 
to have examined each age at marriage with each sized family and subsequent 
life incidental to each sized family, this could readily have been ascertained, but 
the voluminous statistics involved present an almost insuperable obstacle to its 
accomplishment. However, statistics are published in the " Vital Statistics " of 
New South Wales for the two years 1901 and 1902 which show the age at 
marriage, the number of offspring, and the duration of life after marriage, but 
we are unable to connect mothers of each sized family with the duration of 
marriage. One table in the " Vital Statistics " shows the ages at marriage in 
quinquennial groupings, together with the durations of marriage by single years 
and the total offspring. In order to obtain from this table the average number 
of children born to women marrying in each quinquennial group, and who survived 
the reproductive period, I have taken the earliest duration such that if added 
to the latest year of such group the sum would be 49. Thus for age at marriage 
under 20 the duration of marriage was 29 years and upwards ; for age at marriage 
20 — 25 years the duration was 24 years and upwards; and so on. From the 
table referred to I have compiled the information shown in columns 2, 3 and 4 
in Table XVII. Another table in the " Vital Statistics " shows the ages at 
marriage in single years and the duration of marriage also in single years, but 
not the number of offspring, and from this table I have computed for each single 
year of age at marriage the mean duration of life beyond age 46, and the results 
appear in Table XVIII. The means of the quinquennial groups are shown in 
the fifth column of Table XVII. Although the two sets of women shown in the 
* Biometrika, Vol. i. Part i. p. 33. 
