114 HUMAN LONGEVITY. 



Previously, however, to this more scientific direction of the 

 doctrine of averages, it had already received what we may 

 call a mercantile application, in relation to the very topic 

 now before us ; viz. the estimate of human longevity. A new 

 and vigorous traffic has sprung up within the last eighty years, 

 of which the duration of life is the subject and basis. We 

 need not enlarge here upon the principle or history of Life 

 Assurance as a branch of actual business. Originating in 

 England, it is here especially that it has grown and diffused 

 itself so as to become an essential part of our social policy ; 

 a natural, if not necessary, result of those complex relations 

 of property and family connections, which are created by high 

 civilisation, personal freedom, and political security. And 

 though partially defaced by certain evils inseparable from all 

 human institutions, we may regard the system as one con- 

 ducing largely to the interests and welfare of the community. 

 As interpreters of the averages of life, and of the various 

 conditions affecting its duration, Insurance offices in their 

 present extension have become our best guides ; and their 

 tables and calculations, though modified materially of late 

 years, do singularly expound that uniformity of results which 

 arises out of these numerous and extensive records of age and 

 death. Mathematics have lent their aid to the calculation, 

 and given to it many of the conditions of an exact science. 



Still more important documents as to human longevity are 

 those furnished by the English Decennial Census, and the 

 annual reports of the Registrar-General. In these the results 

 are derived from the total population of the kingdom ; and 

 so admirably recorded and classified as to afford not solely 

 numerical conclusions respecting the several periods of age 

 attained, but also much and curious knowledge as to the 

 circumstances and conditions which affect the average dura- 

 tion of life in different classes. Those who desire more 

 detailed information on this subject cannot do better than 



