LIFE. 
The probability that a life of any pre- 
sent age shall continue a certain number of 
years, or shall attain to any other given age, 
is the fraction whose numerator is the num- 
ber of the living in the table opposite to the 
given age, and the denominator the number 
opposite to the present age of the given 
life. Thus the probability that a life of 25 
shall attain to the age of 46, or live 20 years, 
3248 ■ ^ 
is . The difference between this frac- 
4760 
tion and unity gives the probability that the 
event will not happen ; the probability that 
a life of 25 will not live 20 years, is there- 
fore , consequently the odds of living 
4760 , 
to dying in tliis period are more than 2 to 
1. The probability that a person of 32 
years of age shall attain to 59 years, ap- 
2120 
pears by the table to be or nearly an 
even chance. 
In order to find the expectation of life at 
any age, from a table, like the above, which 
shows the number that die annually at all 
ages, divide the sum of all the living in the 
table, at the a^e whose expectation is re- 
quired and at all greater ages, by the sum 
of all that die annually at that age and 
above it; or, which is the same, by the 
number of the living at that age ; and half 
unity subtracted from the quotient will give 
the expectation required. Thus, at the age 
of 65, the sum of all the living at that and 
all greater ages, is 18,580 ; the number 
living at that age is 1,632 ; and the former 
number divided by the latter, and half 
unity subtracted from the quotient, gives 
10.88 for the expectation of the age of 65. 
In this manner the following table is 
formed. 
TABLE II. 
Shewing the Expectations of Human Life at every Age, deduced from the Northampton 
Table of Observations. 
Ages. 
Expect. 
Ages. 
Expect. 
Ages. 
Expect. 
Ages. 
Expect. 
Ages. 
Expect. 
Ages 
Expect' 
0 
25.18 
17 
35.20 
33 
26.72 
49 
18.49 
65 
10.88 
81 
4.41 
1 
32.74 
18 
34.58 
34 
26.20 
50 
17.99 
66 
10.42 
82 
4.09 
2 
37.79 
19 
33.99 
35 
25.68 
51 
17.50 
67 
9.96 
83 
3.80 
3 
39.55 
20 
33.43 
36 
25.16 
52 
17.02 
68 
9.50 
84 
3.58 
4 
40.58 
21 
32.90 
37 
24.64 
53 
16.54 
69 
9.05 
85 
3.37 
5 
40.84 
22 
32.39 
38 
24.12 
54 
16.06 
70 
8.60 
86 
3.19 
6 
41-07 
23 
31.88 
39 
23.60 
55 
15.58 
71 
8.17 
87 
3.01 
7 
41.03 
24 
31.36 
40 
23.08 
56 
15.10 
72 
7.74 
88 
2.86 
8 
40.79 
25 
30.85 
41 
22.56 
57 
14.63 
73 
7.33 
89 
2.66 
9 
40.36 
26 
30.33 
42 
22.04 
58 
14.15 
74 
6.92 
90 
2.41 
10 
39.78 
27 
29.82 
43 
21.54 
59 
13.68 
75 
6.54 
91 
2.09 
11 
39.14 
28 
29.30 
44 
21.03 
60 
13.21 
76 
6.18 
92 
1.75 
12 
38.49 
29 
28.79 
4.5 
20.52 
61 
12.75 
77 
5.83 
93 
1.37 
13 
37.83 
30 
28.27 
46 
20.02 
62 
12.28 
78 
5.48 
94 
1.05 
14 
37.17 
31 
27.76 
47 
19.51 
63 
11.81 
79 
.5.11 
95 
0.75 
15 
36.51 
32 
27.24 
48 
19.00 
64 
11.35 
80 
4.75 
96 
0.50 
16 
35.85 
These tables suggest an easy method of 
finding the number of inhabitants of a place 
from the bills of mortality ; for, supposing 
the yearly births and deaths equal, it is 
only necessary to find in the way above de- 
scribed, tlie expectation of an infant just 
born, and this multiplied by the number of 
yearly births will be the number of inha- 
bitants. 
From all the observations which have 
been made on the bills of mortality of dif- 
ferent places, the fact is fully ascertained 
that the duration of human life is greater 
in all its stages in country parishes and mo- 
derate sized towns, than in large and 
crowded cities. According to Simpson’s 
correction of Smarts Table for London, 
only one in 44 of the inhabitants attain to 
the age of 80 years ; Dr. Price gives the 
proportion somewhat greater, or about 1 in ' 
40, but observes that of those who are na- 
tives of London, a much less proportion 
/ 
