[ 43 ° ] 
grows lefs and lefs precarious till it acquires its utmoft 
vigour at I o or 1 5 ; and of the living at this age, not above 
I in 70 or 8 o dies annually in the world lituations; and 
in the heft htuations, not above i in 1 50 or 1 60. Af- 
ter 15, life declines, and continues to do fo more and 
more, till it becomes quite extindt in old age. If, there- 
fore, in any lituation, the inhabitants confift moreof per- 
fons in mature life, and yet die fafter, it mull be owing 
to fome particular caufes of mortality that operate there. 
This is the cafe in all towns where any obfervations have 
been made. Manchefter, in particular, is not only kept 
up, but increafes fall, by removals to it of perfons in the 
prime of life. The country round it increafes likewife ; 
but it is by an excefs of the births above the deaths; that 
is, by acceffions to it of children in the very feebleft part 
of life. This ought to raife the proportion of annual 
deaths to inhabitants in the country, much above the 
fame proportion in the town ; but, inftead of this, it is 
near one-half lower. 
It may be needlefs to add any thing to thefe obferva- 
tions. 
In order, however, to put this matter out of all doubt, 
I will obferve farther, that it appears in fa6t, from the 
accounts furnillied by Dr. percival, that the number 
of inhabitants in the periods of life when mankind die 
fafteidr^^’ (that is, in the firft and laft ftages of life), is con- 
^n) In towns, about a fomtli of the inhabitants die commonly between 14 
and 51; a fifth or lixth die at 5 1 and upwards; and the remainder die under 
15. In country pariflies and villages about a fifth die between 14 and 5 1 ; about 
two-fiftlis at 51 and upwards; and the remainder uiider 15. 
fiderably 
