4i8 MEMOIKSofthe 
I Ihall have from the fecond -,_ , , from the third ■ y^c. 
And accordingly if ^ be r= lOO and c ^= 6 (the number of pounds 
that ICO /. put out to intereft brings at the years end) and confe- 
quently my ihare of certainty from one reporter be := y§| 
(which is the prelent value of any fum to be paid one year hence, 
viz. 1699) the proportion of certainty coming to me from a fecond 
will be Tuf multiplied by r^f (which is the prefent value of mo- 
ney to be paid after two years) and that from a third reporter 
r= f §1 thrice multiplied into itfelf, (the value of money payable 
at the end of three years,) ^c. 
Corollary. And therefore, as at the rate 0^6 per Cf;/f.interefl, 
the prefent value of any fum payable after I2 years, is but half 
the fum 5 fo if the probability or proportion of certitude tranf- 
mitted by each reporter be iff, the proportion of certainty after 
12 fuch tranfmiflions, will be but as a half 5 and it will be by 
that time an equal lay, whether the report be true or not : In the 
fame manner, if the proportion of certainty be fet at i§f, it will 
come to a half ftom the 70th hand 5 and if at f J^f from the 
595th hand. 
'Prop. II. concerning concurrent teftimonies, if two concurrent 
reporters have each of them as § of certainty, they will both give 
me an affur^nce of f^- or of 55 to one 5 if three an affurance of 
It J, or of 21 5 to one : For if one of them gives a certainty for 
f 200/. as of I', there remains but an affurance of f or of 200/. 
wanting to me, for the whole 5 and towards that, the fecond attef- 
tor contributes, according to his proportion of credibility , that is, 
to ^ of certainty before had, he adds ^ of the # which was want- 
ing 5 fo that there is now wanting but f of f , that is f 6" 5 and 
confequently I have from them both j J of certainty 3 lb from 
three Hh ^C 
That is if the firft witncls gives me — ■ — of certainty, and 
there is wanting of it — — , the fecond atteftor will add — j — 
of that — ■ — ; and confequently leave nothing wanting but 
— - — of that — —— ■ ^ — ; and in like manner the third 
a-r c a-\- c a -f- c^ ^ 
atteftor adds his ^ of that =i^ and leaves wanting only 
T^' ^^' Cord' 
