These tables suggest an easy method of finding the number of inhabitants of a place from the bills of mortality; for, sup posing the yearly births and deaths equal, it is only necessary to find, in the way above described, the expectation of an infant just born, and this multiplied by the number of yearly births will be the number of inhabitants.
From all the observations which have been made on the bills of mortality of different places, the fact is fully ascer tained, that the duration of human life is greater in all its stages in country parishes and moderat6 sized towns, than in large and crowded cities. According to Simp. son's correction of Smart's Table for Lon don, only one in 44 of the inhabitants at tain to the age of 80 years; Dr. Price gives the proportion somewhat greater, or about 1 in 40, but observes that of those who are natives of London, a much less proportion arrive to that age. The pro portion of the inhabitants of other places that live to the age of has been found as follows: At Edinburgh ..... 1 in 42 Vienna 1 in 41 Breslaw 1 in 41 Berlin 1 in 37 Norwich I in 27 Northampton . . . 1 in 24 Pais de Vaud . . . 1 in 21
Among any considerable number of lives selected from the common mass, .meh as the nominees to a tontine, or the members of an assurance or annuity so ciety, the duration of life will always be found greater than it is represented by tables formed from general bills of mor tality. Thus, 31. Kersseboom found that among the state annuitants in Holland, 1 in 14 lived to upwards of 80 years of age, and the nominees to the life annuities granted by the governments of France and Great Britain, have been found to live longer than the duration given by any table formed from bills of mortality. In some few country situations, where the injurious habits and artificial mode of liv ing which prevail in large cities have made little progress, the duration of life has been found unusually great ; thus, at Ackworth, in Yorkshire, 1 in 14 died turn ed of 80 years of age ; and, according to an account of the parish of Bingham in New England, in the first volume of " Me moirs of the American Academy," the number of deaths in 54 years had been 1113, of which 1 in 13 had survived 80 years.