[ 28 o 3 
crcafe j which indeed is very Tmall, snd I believe 
much diminiflied, by the emigration of great num- 
bers to our colonies in America, and-fettlementselfc- 
where, 'or by our wars, and Ioffes at fea. So that if 
it was not for the acceffion of Foreigners, and thofe 
who come from^ Scotland and Ireland, the increafe 
would be very inconfiderable, if any at all; which 
by the way fhews the reafonablenefs and good policy 
of encouraging Foreigners to fettle among us. How- 
ever,^ let us fuppole the annual increafe to be 18000, 
and it will be ealy from thence to find in what time 
the number of the people may be double, or in any 
given proportion} not by dividing 6,000,000 by i8oco, 
confidering the annual increafe as aconftant quantity, 
which is the method Sir William Petty ufes by mif- 
take, or perhaps not knowing how to do it other- 
wife } but by making this annual increafe continually 
to increafe as the whole number does. Let us pro- 
pofe the queftion firft in general, the number of peo- 
ple being unknown, which is this : 
The proportion being given of the living to the 
dead in one year, and alfo the proportion of the 
bixths to the dead, the number of the people be- 
ing unknown} to find in what time the people fhall 
be in any given proportion, to what they are at pre- 
fent. . ^ 
Suppofe n to be the unknown number of the peo- 
ple at prefent } and let the living be to the dead, m 
one year, as / to i, and the dead to the births as 
I to by the proportion given to what their number is 
at prefent as ^ to i, and the number of years required 
to be y. ^ u 
It 
