on the Experience of the Equitable Society. 341 



and/= 11-5179180, and hl«> 11-517918 - ii^^ be- 

 ing = i^f— • When y = and z« = 1, hlz = -2-90903 



= h 1 -— -, so that about one in a million only would survive at 



115. 



7. It is obvious that, according to this formula, the value 

 of z can never become wholly extinct, and that a population 

 may be imagined great enough to have an individual living at 

 any given age : but notwithstanding Mr. Gompertz's ingenious 

 speculations on patriarchal longevity, it can scarcely be ad- 

 mitted that the analogy is sufficiently strong to justify such 

 a conclusion respecting more modern times ; to say nothing 

 of the population of the whole world as a limit which would 

 require to be considered. 



8. The results of the formula are exhibited in the following 

 table, in which they are compared with Mr. Babbage's table 

 of the Equitable Experience, with the Carlisle table, and with 

 the table published in the Philosophical Transactions for 1826. 



9. I am at a loss to understand how you will be able to 

 reconcile the numbers of the first column of this table, with 

 the opinion that " the experience of the Equitable Office con- 

 firms the accuracy of the Northampton table," which is re- 

 presented by the fourth column, on the supposition that a 

 given number of individuals about 55 is to be compared. From 

 this age, and as far as 85, the first column certainly represents 



the 



