844 
DE. EAEE ON THE CONSTETJCTION OF LIFE-TABLES. 
the rate of increase r is nearly the same for the two sexes. From the age of 40 to 50, 
and 50 to 60, the mortality of males increases at a rate intermediate between the rates 
of manhood and mature age. 
Females. 
Limits of 
ages. 
15 to 55 
or 
20 to 
50 
p=l-0149 
-00642 
55 to 95 
or 
60 to 
90 
r:=l-0874 
Xr=-03639 
Males. 
15 to 45 
or 
20 to 
40 
r=l-0148 
Xr= -00640 
65 to 95 
or 
60 to 
90 
r=l-0874 
Xr=-03640 
The subjoined Table exhibits the series of values for m derived from the hypothesis 
of two constant rates, and from direct observation. The values of r for females may be 
evidently applied to males in every period, except in the ten years of age, 40 to 50. 
Mortality (m) of males and females, (1) derived from observation, and (2) from the 
hypothesis that m increases at the preceding rates. 
Annual Moetality to 100 constantly living at each age (m). 
Precise age. 
Males. 
Females. 
By observation. 
By hypothesis. 
By observation. 
By hypothesis. 
20 
•691 
•696 
•765 
•760 
30 
•818 
•807 
•894 
•882 
40 
•928 
•935 
•998 
1-022 
50 
1-273 
1-083 
1-192 
1-185 
60 
2-294 
2-329 
2-162 
2-177 
70 
5-486 
5-385 
4-992 
5-033 
80 
12-817 
12-451 
11-866 
11-633 
90 
28-350 
28-785 
26-711 
26-891 
100 
40-000? 
66-550? 
j 45-000? 
62-160? 
The observations on the numbers living and dying of the age of 95 and upwards are 
exceedingly uncertain ; and it is probable that many of the persons believed to be 100, 
&c., are really persons five or ten years younger f so that these values of by the hypo- 
theticaTmethod, are probably as correct as the direct numbers. 
I shall now notice briefly the application of this hypothesis, fii'st suggested by 
Mr. Gompektz, and applied by him to the interpolation of the Northampton and other 
Tables^. Mr. Edmonds, in 1832, extended the “Theory,” and applied it to the con- 
struction of three Life-Tables •f’. He gave an elegant formula, similar in principle to 
that of Mr. Gompektz, from which the curve of a Life-Table can be deduced, upon the 
above hypothesis. 
* Philosophical Transactions, 1825, paper by B. Gompebtz, Esq., F.E.S. 
t Life-Tables founded upon the discovery of a Numerical Law regulating the existence of every Human 
Being, &c. By T. E. Edmonds, B.A., 1832. 
