expressed by a New Formula. 1 3 



years, and the mortality 9 months before birth is equal to the 

 mortality at the age 90 years. It would hence follow that mor- 

 tality above the age of 90 years is not measurable by the new 

 formula, because the mortality before the time of conception is 

 not so measurable. It may be further stated that, according to 

 the English Life Table for males, the mortality in the first month 

 from birth-time is 64 per cent, per annum. This number does 

 not differ much from 56*9, the maximum mortality given by the 

 formula. So high a rate of mortality as 64 per cent, per annum 

 in the first month, ought not to excite surprise; for in the 

 deaths of the first month from birth-time, it may be presumed, 

 are included the deaths arising from miscarriage and premature 

 birth in the eighth and ninth months from conception. 



There is some ground for believing that 9 months, the period 

 of gestation in the human female, is the atomic indivisible unit 

 of age in the period of childhood. It has been shown that, ac- 

 cording to the new formula, the mortality at any age varies 



i i 



inversely as (a + t} k or (l + £)fc,when reduced to its simplest form, 

 1 + ^ representing absolute age measured from the ideal zero 

 of life. This quantity (1 + 1) is apparently contained in the 

 new formula for the sake of its convertibility from numbers into 

 logarithms by the formula 



log(l+0=/-| 2 + J + &c. 



The lowest whole number which can represent t in the above 

 formula is unity ; that is to say, log (1 + 1) or log 2 is used at the 

 first step which can be made in the application of the new for- 

 mula in proceeding from the ideal zero to the ages 1, 2, 3, &c. 

 The mortality immediately after the time of conception is the 

 very earliest that can be measured by the formula, and then 1 + 1 

 is represented by 1 + 1 or by 2. It being known that the 

 absolute age of conception is 18 months from the ideal zero of 

 life, it ensues that the 18 months contain two units each of 9 

 months. 



On inspection of Table VI. (hereunto annexed), in which are 

 presented in a condensed form the results of all the chief obser- 

 vations on the mortality, according to age, of the male popula- 

 tions of Sweden and England, it will be seen that the new for- 

 mula fails to express the apparent law at ages exceeding 85 

 years. According to the new formula, the survivors at the age 

 85 years disappear more rapidly with age than they are sup- 

 posed to do by any other law. According to observation, both 

 in Sweden and England, the average rate of mortality in the de- 

 cennial interval of age from 85 to 95 years is just twice as great 

 as the average rate of mortality in the decennial interval of age 



