438 Of the, Checks to Population Bk. ii. 



than was before furnished, and of shewing at the 

 same time the uncertainty of estimates from the 

 births alone, particularly with a view to the pro- 

 gress of population during particular periods. In 

 estimating the whole population of a large coun- 

 try, two or three hundred thousand are not of 

 much importance; but, in estimating the rate of 

 increase during a period of five or ten years, an 

 error to this amount is quite fatal. It will be al- 

 lowed, I conceive, to make an essential difference 

 in our conclusions respecting the rate of increase 

 for any five years which we may fix upon, 

 whether the addition made to the population 

 during the term in question is 63, 000 or 

 277,000, 115,000 or 456,000, 659,000 or 

 417,000. 



With regard to the period of the century pre- 

 vious to 1780, as the registers of the baptisms 

 and burials are not returned for every year, it is 

 not possible to apply the same corrections. And 

 it will be obvious that, in the table calculated from 

 the births previous to this period, when the re- 

 gisters are only given for insulated years at some 

 distance from each other, very considerable errors 

 may arise, not merely from the varying proportion 

 of the births to the population, on averages of five 

 years, but from the individual years produced not 

 representing with tolerable correctness these ave- 

 rages.* A very slight glance at the valuable table 



* From the one or other of these causes, I have little doubt, 

 that the numbers in the table for 1 760 and 1 770, which imply so 



