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ciered, that if migrations lelTenthe number of deaths, they 
alfo leflen the number of inhabitants ; and that it depends 
intirely on the ages at which the inhabitants remove 
from a place, whether the effebt of their removal lhall be 
lowering or railing the proportion of the annual deaths to 
the number of inhabitants. In the prefent cafe, the 
truth appears to be, that the moll common age of mi- 
gration from the country is fuch as raifes this proportion 
in the country. This will be evident from the fol- 
lowing conliderations. The period of life in which per- 
fons remove from the country to fettle in towns, is chiefly 
the beginning of mature life, or from the age of i o or 
15 to 25 or 30. In infancy, none migrate; and in the 
decline of life, it is more ufual to retire from towns than 
to remove to them. Towns, therefore, will be inhabited 
more by people in the firmefl: parts of life ; and, on the 
other hand, the country will be inhabited more by peo- 
ple in the weakeft parts of life ; and the confequence of 
this is, that in the country, the inhabitants mufldie falter 
in proportion to their number than they otherwife would, 
and that in. towns they muft die more llowly. In parti- 
cular, the number of children is always much greater in 
the country than in towns ; and this is a circumitance 
which mufl; be extremely unfavourable to the former: 
for it is well known, that there are no years of life, in 
which fo many of a given number die, as the firft three 
or four years. Till the age of live, human life, like a; 
lire beginning to burn, is very feeble ; and in fome fltii- 
aiions more than half, and in others, a third or fourth 
of all that are born die before that age. After this, life 
