198 ESSAY ON PROBABILITIES. 



called a temporary annuity on the life of B to last t 

 years, provided B should live t years. 



1. Any simple status on the existence or termination 

 of which a benefit depends, is denoted by juxtaposition 

 of large and small letters, the large letters denoting 

 separately the values of annuities on given lives or status, 

 the small letters (or rather certain small letters, m, n, t, 

 for the most part) denoting given terms of years. 

 Thus A B C t is in existence as long as t years last, 

 provided A, B, and C (or the persons on whom 

 annuities now granted have these values), remain alive 

 all the time. 



2. A compound status, or one which exists as long 

 as either of two or more status remain, is denoted by 

 colons placed between the symbols of the simple status ; 

 thus A : B : t is in existence as long as A, or B, or t 

 years, any or all, are in existence. The symbol is un- 

 meaning between two certainties : thus, n: n + t is 



3. A bar placed over two status indicates that the 

 one is to succeed the other and that the compound 

 symbol denotes a status in being as long as the one, or the 



other after it shall exist : thus A P denotes a status 

 which remains in being during the life of A, and also 

 during a life to be named at the end of the year in 

 which A dies, having then the value P. If there be 

 occasion, a thicker bar, or one with an accent, or a 

 double bar, may be used where there are two successions 

 involved, between which it is necessary to distinguish. 



4. The symbol | in all cases gives the whole symbol 

 the meaning of the present value of a benefit to be re- 

 ceived, and a figure attached, as in | 4 , denotes'the rate 

 per cent, at which the value is to be calculated. This 

 benefit is always 11. at each one or more payments. The 

 description of the status which must end before the benefit 

 begins will be found on the left of | ; and the description 

 of the status during which the annual payments of the 

 said benefit are to last will be found on the right. It 

 is further to be understood that the first payment made 



