480 On the Fruitfulness of Marriages. Bk. ii. 



of population is going forwards, the average age 

 of marriage is less than the average of death, and 

 then the proportion of marriages, compared with 

 the contemporary deaths, will be too great to re- 

 present the true proportion of the born living to 

 marry ; and, to find this proportion, we must > 

 compare the marriages of any particular year 

 with the deaths of a subsequent year at such a 

 distance from it in the registers, as is equal to the 

 difference between the average age of marriage 

 and the average age of death. 



There is no necessary connection between 

 the average age of marriage and the average 

 age of death. In a country, the resources of 

 which will allow of a rapid increase of popula- 

 tion, the expectation of life or the average age of 

 death may be extremely high, and yet the age of 

 marriage be very early ; and the marriages then, 

 compared with the contemporary deaths in the 

 registers, would (even after the correction for 

 second and third marriages) be very much too 

 great to represent the true proportion of the born 

 living to marry. In such a country we might 

 suppose the average age of death to be 40, and 

 the age of marriage only 20 ; and in this case, 



may in some cases be taken as synonymous with births. If we 

 had the deaths registered of all the births which bad taken place 

 in a country during a certain period, distinguishing the married 

 from the unmarried, it is evident that the number of those who 

 died married, compared with the whole number of deaths, would 

 accurately express the proportion of the births which had lived to 

 marry. 



