and the Intensity of Human Life. 203 



perly, termed expectation of life*; it will then appear, that the 

 superior intensity of female lives is in a more considerable pro- 

 portion amongst the inferior classes, than amongst those se- 

 lected as existing under a series of circumstances generally 

 favourable to the preservation of life at all its stages. This 

 difference, in the aggregate, will also be conspicuous in the 

 detail, though with some variation in the progressive ratios, 

 and likewise in the respective periods of increase and de- 

 crease. 



Any two laws of mortality, the cme applicable to male and 

 the other to female lives, both of the same class of selection^ 

 will, unless defective, present all those differences in their pro- 

 per light. 



With reference to either sex, a very considerable difference 

 takes place in the maximum of intensit)', as also in the year 

 of age at which it occurs, between lives of a superior and those 

 of an inferior class. In the instance °of lives belonging to a 

 select class, to which the annuitants may generally be assimi- 

 lated, the maximum of intensity for females, and expressed by 

 a required quantity of the living for producing one death be- 

 fore the expiration of another year, is 270, and referable to 

 fifteen completed years of age; whilst it is 236 only for males, 

 and referable to the age of fourteen years : and for the inferior 

 class of either sex, involving the great mass of people who exist 

 under circumstances of hardship and privation, the maximum 

 thus expressed scarcely exceeds a hundred, referable to an 

 earlier age even than that of ten years f ; after which the in- 

 tensity of life, for this class, begins to decrease. Facts of this 

 description abundantly testify how inapplicable the law of 

 mortality must be to any other class than the one to which it 

 expressly refers. 



A principal feature, indicative of the quality of lives to 

 which any such law may be referable, is the comparative num- 

 ber of population, whether general or select, and of the speci- 

 fied sex, that should permanently result from any given quan- 

 tity of annual births, compensating an equal quantity of deaths 

 understood to occur during the same interval. This fiction, 

 of an absolutely stationary population, is requisite for enabling 

 the stated law of mortality to fulfill at once txao indications: 

 first, the progressive decrement, from year to year, of indivi- 



• The true expectalion is the period of years at the expiration of which 

 the living, at any stated age, will be reduced to /io// their number ; thereby 

 indicating an equal probability of outliving that period or not. 



•j- These remarks arc not stated with greater precision, because the law- 

 applicable to the inferior class alluded to (being ihajiftit and last) is not 

 vet completed, 



2 D 2 duals 



