C 77 3 
If the ordinate of a curve be 7 j its area will 
r* 
, J_ _J 
a 1 a 2 r z ar z 
If the ordinate of a curve be — » its area will 
2 2 2Z « 2 
a'r 1 a z r z ar z 
I beg leave, in this place, to fake notice, that 
in the theorem in line 12. page 63. of the fecond 
edition of my book of annuities on lives, inftead 
of ‘P, it ought to be t. <p } where n and p reprefent 
the complements of the age, in the beginning and 
end of a given interval of time. 
And I defire the reader of that edition to adapt 
the fourth article of the rule put in words at length, 
in page 64, to the theorem fo corre&ed : then the 
folution there given, and that in page 21. of thefirft 
edition, will perfe&ly agree ; provided that the de- 
crements of life be fuppofed, in both cafes, uni- 
form, from an age given, to the extremity of old- 
ace. 
I muft alfo take notice of an accidental error, that 
has crept into the 25th propofition of the fecond 
edition ; which I chufe to correct as follows 5 
1. Let the firft line of the propofition, and part 
of the fecond line, as far as A exclufive, be erafed. 
2. Let the folution proceed thus: lince the life 
of A is fuppofed to be worth 14 years purchafe, 
when intereft is at 4 per cent, per annum, it follows, 
1 from 
