( nr) 
* 
ria percurric lineolam /A'i corpus aliud in circulo ineadem di- 
ftantia motum percurret arcum — & Area fe<ftori$ 
4 
b 
Circuli & Traje<ftorix fimul defcriptx erunt— * Kit x lqH 
a 
&Ktfx~CN, qux dux Arex funt in ratione data, fcil. ut b ad 
4. Adeoque ubi eft a = b, uti fit in Spirali Hyperbolica, 
Area fic defcripta erit Temper xqualis Arex fe&oris circularis in 
xquali tempore defcriptx. 
November 24. 1713. 
ILL Rules for correcting the ufual Methods of computing Amounts 
and prefent V dues , by Compound as well as Simple Inter eft ; and 
of fiating Intereft Accounts. Offer d to Conftderation t by 
Thomas Watkins, Gent . F . R. S. 
I. Of Compound Intereft. 
T HE Suppofition whereorf the Method of computing 
by Compound Intereft is founded 5 viz. That all In- 
tereft Money, Rents, drc. are or may be conftantly receiv’d, 
and put out again at Intereft, the Moment they become due, 
without any Charge, or Trouble, being impracticable ; there- 
fore all Computations by this Method (except of Fee-Simples 
or other Perpetuities) muft needs be erroneous. Thus for 
Inftance, the Amount of a Sum of Money, or Annuity, for 
want of Dedu&ions out of the Profits, for the unavoidable 
Trouble, Charge, and Delay in the Management, will be too 
great : and for the fame reafon, the prefent value of a Sum 
of Money payable in any time to come, will be too little ; alfb * 1 
the prefent value of an Annuity (being only the Amount of 
the difference between the Annuity, and Intereft of the faicl j 
prefent value) will be too much. But in long terms of Years* ‘ 
as that difference becomes.lefs To does the Error, as the term is > 
great?-; 
