32 Data for the Problem of Evolution in Man 
TABLE II. 
Births per 100 Wives in Age Groups. Experience of Victoria from Marriages 
of 1897. 
Age Group 
Mean Annual 
Marriages 
Ante-nuptial 
Conceptions 
Unprejudiced 
Marriages 
Mean Annual Births 
from 9 to 12 months 
after Marriage 
Births per cent, 
of unprejudiced 
Marriages 
Under 20 
767 
338 
429 
93 
21-67 
20 and under 25 
3122 
898 
2224 
732 
32-91 
25 „ 30 
2235 
437 
1798 
740 
41-16 
30 „ 35 
775 
144 
631 
238 
37-72 
35 „ 40 
349 
45 
304 
60 
19-73 
40 „ 45 
130 
16 
114 
9 
7-89 
Its equation, the unit of x being five years, is 
with the mean at 28-26 years and the mode at 27'00 years. The range is from 
13'43 to 46-63 years. 
Dr Alice Lee, using Mr Sheppard's corrections, found 
/ 7' \ '8365 / \ 1-2825 
with the mean at 28-264 years and the mode at 26 703 years. The range is from 
14-65 to 45-19 years. 
Here again the resulting form of the curve suggests that Sheppard's corrections 
are unsuitable, and probably the former equation is the better*. 
Now whether Mr Powys' or Dr Lee's curves are used we see very clearly : 
(a) that the fertility of women begins earlier in Victoria and ends later, but 
(6) that the maximum fertility in New South Wales is reached almost three 
years earlier than it is in Victoria, say 24 years as compared with 27. 
The more rapid development of women in New South Wales is undoubtedly- 
due to its much warmer climate. Nearly one-half of the population of each colony 
is concentrated in their capital cities ; the mean annual temperature of Sydney 
being 63° F., and that of Melbourne being 57° F. 
We should expect the Victorian fertility to end later under these circum- 
stances ; that it also begins earlier is noteworthy. The year's advance on New 
South Wales may not really be a sensible difference ; it may result from the large 
* Clearly there is not in any of these curves really high contact at either end of the range, and 
the discovery of suitable corrections for the moments in such cases is one we would urge upon 
any unemployed mathematician. K. P. 
