, 74 A R I T H 
The Rule for ufing the Table is this: Multiply the princi¬ 
pal by the rate, both in pounds; multiply the product by 
the number of days, and divide this lift produdt by ioo; 
then take from the table the feveral linns which (land op- 
pofite the feveral parts of the quotient, and adding them 
together will give the intereft required. 
Ex. What is the intereft of 225I. 10s. for twenty-three 
days, at 4A percent, per annum? 
Princ. 22p; ^ 
againft 200 is 
30 
3 
•O ’3 
C09 
Anfwer o 12 9 1-85 true in 
Rate 
22 5'5 
4'5 
1014.-74 
75 da Y s _il 
100 ) 23339' 2 5 •" 
2 33'39 2 5 
1. s- d. q. 
o 10 11 2-03 
017 2-90 
o O 1 3-89 
000 0-79 
000 0-24 
H the laft place of decimals. 
Another ingenious and general method of computing 
intereft, is by the following final! but comprehenfive Table : 
A General Interest Table, 
By which the Intereft of any Sum, at any Rate, and 
for any Time, may be readily found. 
c n 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
20 
30 
40 
5° 
60 
70 
80 
90 
100 
200 
400 
>er Cent. 
3 1 per Ct. 4 per Cent. 
ii 
per 
Ct 
; pei'Cent 
s. 
a. 
1 . s. 
d. 
1 . s. 
d. 
1. 
s. 
d. 
1 . 
s. d. 
2 * 
2 i 
3 
3* 
4 | 
Si 
6 
65 
si 
H 
71 
8* 
9 t 
7 t 
9 
1 ij( 
1 1 
9 l 
I 
1* 
1 
2 t 
1 4* 
11| 
I 
3 § 
I 
3 t 
1 
si 
I 75 
I 
I 
4 
I 
6* 
1 
8* 
1 11 
I 
0 3 
I 
H 
I 
9 
1 
2 2* 
I 
5 * 
I 
I 
3 >5 
2 
2 i 
2 Si 
I 
I 
I I 
2 
2 * 
2 
55 
2 8 ^ 
3 
3? 
3 
10 
4 
42 
4 
Hi 
5 5 t 
4 
11 
5 
9 
6 
64 
7 
4 A 
8 2-£ 
6 
6| 
7 
8 
8 
9 
9 
10* 
IO II^ 
8 
2 i 
9 
7 
IO 
1 2 
3 * 
13 8* 
9 
10* 
I I 
6 
13 
It 
14 
95 
16 5* 
11 
6 
13 
S 
15 
4 
1 7 
3* 
19 2 
13 
15 
4 
17 
6 * 
3 9 
8| 
I 
I II 
1 4 
95 
»7 
3- 
J 9 
H 
C 
2 
2 * 
1 
4 7t 
16 
Si 
*9 
2 
1 1 
II 
I 
4 
8 
I 
7 4t 
12 
io£ 
1 18 
4 * 
2 3 
IO 
2 
9 
3t 
2 
14 95 
9 
3t 
2 17 
6*3 5 
9 
3 
1 3 
1 *4 
4 
2 2 i 
This Table contains the intereft of iool. for all the fe¬ 
veral days in the'firft column, and at the feveral rates of 
3j 4 a., and 5, per cent, in the other five columns. 
’ fo'find, the Interejl of iool .for any other time: as one year 
and 278 days, at fL per cent. Take the fums for the fe¬ 
veral days here as below. 
The Intereft for 1 year 
Againft 200 days is 
_-- 70 days is 
___ 8 days is 
4 10 
2 9 
o 17 
o 1 
o 
3f 
3 ? 
11 
Intereft required 
718 6 
For any other Sum than iool. Firft find for iool. as above, 
and take it fo many times or parts as the fum is of iool. 
Thus, to find for 355I- at 4 |, for one year and 278 days ; 
Firft, three times the above fum, 
(for 300I.) is 23 15 8£ 
\ (for 50I.) is 319 3* 
of this (for 5k ) o 7 11 
So for 355 it is 28 2 ipt 
When the intereft is required for any other rate than 
thofe in the Table, it may be eafily made out from them. 
So one-half of five is 2 £, one-half of four is 2, one-half 
of three is i 3 -, one-third of three is i, one-fixth of three 
M E T I C. 
is i, and one-twelfth of three is 4 . And fo, by parts, orL 
by adding or fubtraffing, any rate may be corredtly made 
out. 
COMPOUND INTEREST, 
Called alfo lnteref-upon-Interef, is that which is count¬ 
ed not only upon the principal fum lent, but alfo for its 
interned, as it becomes due, at the end of each ftated time 
of payment:. Although it be not lawful to lend money at 
Compound Intereft, yet in purchafing annuities, penlions, 
&c. and taking leafes in reverlion, it is ufual to allow 
Compound Intereft to the purchafer for his ready money ; 
and therefore it is very neceffary to underftand this fubjeCf. 
Befides the quantities concerned in Simple Intereft, viz. 
the principal p , the rate or intereft of jl. for 1 year r, the 
amount m, and the time n, there is another quantity em¬ 
ployee} in Compound Intereft, viz. the ratio of the rate of 
intereft, which is the amount of il. for 1 time of pay¬ 
ment, and which here let be denoted by R, viz. R = i-}-V. 
Then, the particular amounts for the feveral times may be 
thus computed, viz. As il. is to its amount for any time,, 
lb is any propofed principal fum to its amount for the 
fame time, i. e. 
il. : R :: p : pR the firft year’s amount, 
il. : R :: pR : p R 2 the fecond year’s amount, 
jl. : R :: pR 2 : pR 3 the thud year’s amount, 
and fo on. Therefore in general, pR n —m is the amount 
for the n year, or n time of payment. From whence the 
following general theorems are deduced : 
ift. 
m 
22 pR n 
the amount, 
2d. 
p 
m 
~ bF 
the principal. 
3 d - 
R 
~ V T 
the ratio, 
n 
log. 
of»z—log. of p 
— 
log. of R 
the time. 
From which any one of the quantities may be found, 
when the reft are given. 
For example, fuppofe it were required to find in how 
many years any principal fum will double itfelf, at any 
rate of intereft. In this cafe we muft employ the fourth 
theorem, where m will be — 2 p, and then it is 
\.m—\.p 1 . 2 p — 1 .p log. 2 
U log. R log. R log. R ‘ 
So, if the rate of intereft be 5 per cent, per annum ; then 
R221+-0522:1 "05, and hence 
log. 2 -3010300 , , 
22 =: t-— =2 ---— =2 14-2007 nearly ; that is, 
log. 1-05 -0211893 
any fum doubles in 14-L years nearly, at the rate of 5 per 
cent, per annum Compound Intereft. 
Hence, and from the like queftion in Simple Intereft, 
above given, are deduced the times in which any fum dou¬ 
bles itfelf, at the feveral rates of intereft, both limpleand 
compound, viz. 
r 
< 
'AtSimp.Int. 
At Comp.Int. 
Years. 
Years. 
2 
5 ° 
3 5'0028 
2 — 
40 
28-0701 
3 
33 ? 
23-4498 
3 i 
percent, per ann. 
284 
20-1488 
4 
y 
Intereft, il. or 
2 5 
17-6730 
4i 
any other fum * 
22f 
1 5'747 3 
5 
will double in 
20 
14-2067 
6 
7 
i6f 
3 4 y 
10*2448 
8 
I 2 2* 
9-0065 
9 
8-0432 
IO 
L 10 
7-2725 
The following Table will facilitate the calculation of 
Compound Intereft for any fum, and any numberof years, 
at various rates of Intereft. 
The 
