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live beyond the age of 41. In truth, did all mankind 
lead natural and virtuous lives, that wafte of the fpecies 
which happens in infancy and childhood would not take 
place, and few would die except in old age. The in- 
ference, however, which I have mentioned, cannot be 
made with reafon. It is juft only in the particular cafe 
of an uniform decreafe in the probabilities of living, from 
birth to old age; and this is a cafe that has never exifted. 
In all other cafes, there is not any neceflary connexion 
between the proportion of inhabitants dying annually, 
and the age to which the greater part live. In moft ci- 
ties one-half, as I have juft obferved, of all that are born 
die before two or three years of age. But it cannot be 
imagined, that there is any place where fo many as one- 
half or a third of the inhabitants die every year. 
But to return to Dr. percival’s account of the town and 
parifti of Manchefter. It appears from this account, that 
the number of children under 15, compared with the 
number of inhabitants between 14 and 5 1, is greater in 
the country than in the town of Manchefter, in the pro- 
portion of no lefs than 5 to 4^^;. It follows, therefore, 
that though, in confequence of a conftant influx of peo- 
ple to the town, it is more filled than the country with 
(k) In the town, the number of inliabltants between 14 and 51 is 13779 » 
and 9575 under 15. In the country, the former number is 6481 ; and the latter, 
5545. But the laft number would have been only 45 *^ 3 > proportion of 
the inhabitants between 14 and 51 to the inhabitants under 15 been the fame in 
both fituations. It is owing to this, that the number of perfons in a family in 
the country is 5| ; but in the town only 4I. 
M m m 2 
inha- 
