given principal for 1 month may readily be found, by taking such an aliquot part of the interest for 1 month as the given rate is part of 12 per cent.

Thus,

To find the interest for 1 month at 6 per cent., remove the separatrix two places to the left, and divide by 2.

To find it at 3 per cent., proceed as before, and divide by 4; at 4 per cent., divide by 3; at 2 per cent., divide by 6, etc.

SIX PER CENT. METHOD.*
*

540. By referring to 536 it will be seen that the legal rate of interest in 21 States is 6 per cent. This is a sufficient reason for introducing the following brief method into this work: ANALYSIS. At 6 % per annum the interest on $1

1st. The interest on $1 is $.005 per month, or $.01 for every

2 months;

2d. The interest on $1 is $.000 per day, or $.001 for every 6 days.

From these principles we deduce the

RULE. I. To find the rate: Call every year $.06, every 2 months $.01, every 6 days $.001, and any less number of days sixths of 1 mill.

II. To find the interest: Multiply the principal by the rate.

NOTES.-1. To find the interest at any other rate % by this method, first find it at 6 %, and then increase or diminish the result by as many times itself as the given rate is units greater or less than 6 %. Thus, for 7 % add 4, for 4 % subtract, etc.

2. The interest of $10 for 6 days, or of $1 for 60 days, is $.01. Therefore, if the principal be less than $10 and the time less than 6 days, or the principal less than $1 and the time less than 60 days, the interest will be less than $.01, and may be disregarded.

3. Since the interest of $1 for 60 days is $.01, the interest of $1 for any num

*This method of finding the interest on $1 by inspection was first published in The Scholar's Arithmetic, by Daniel Adams, M. D., in 1801, and from its simplicity it has come into very general use.

ber of days is as many cents as 60 is contained times in the number of days. Therefore, if any principal be multiplied by the number of days in any given number of months and days, and the product divided by 60, the result will be the interest in cents. That is, Multiply the principal by the number of days, divide the product by 60, and point off two decimal places in the quotient. The result will be the interest in the same denomination as the principal

EXAMPLES FOR PRACTICE.

What is the interest on the following sums for the times given, at 6 per cent.?

11 mo. 3 da.

Ans. $24.572.

per cent.?

per cent.?

32. $127.65 for 1 yr. 23 What is the interest of $155.49 for 3 mo., at 6 34. What is the interest of $970.99 for 6 mo., at 5 35. What is the amount of $350.50 for 2 yr. 10 mo., at 7 per cent.? Ans. $120.01+. 36. What is the interest of $95.008 for 3 mo. 24 da., at 41⁄2 per cent. ? Ans. $1.353+. 37. What is the amount of $145.20 for 1 yr. 9 mo. 27 da., at 12 per cent.? Ans. $178.32375. 38. What is the amount of $215.34 for 4 yr. 6 mo., at 3 per cent.? Ans. $249.256+. 39. What is the amount of $5000 for 20 da., at 7 per cent.? 40. What is the amount of $16941.20 for 1 yr. 7 mo. 28 da., at 4 per cent.? Ans. $18277.91—. 41 If $1756.75 be placed at interest June 29, 1860, what amount will be due Feb. 12, 1863, at 7 %?

42. If a loan of $3155.49 be made Aug. 15, 1858, at 6 per cent., what amount will be due May 1, 1866, no interest having been paid?

43. How much is the interest on a note for $257.81, dated March 1, 1859, and payable July 16, 1861, at 7 % ?

44. A person borrows $3754.45, being the property of a minor who is 15 yr. 3 mo. 20 da. old. He retains it until the owner is 21 years old. How much money will then be due at 6 % simple interest? Ans. $5037.22+. 45. If a person borrow $7500 in Boston and lend it in Wisconsin, how much does he gain in a year?

48. A man sold a piece of property for $11320; the terms were $3200 in cash on delivery, $3500 in 6 mo., $2500 in 10 mo., and

e remainder in 1 yr. hole amount paid?

3

mo., with 7% interest;

what was the Ans. $11773.833.

47. May 10, 1859, I borrowed $6840, with which I purchased ›ur at $5.70 a barrel. June 21, 1860, I sold the flour for $6.623 barrel, cash. How much did I gain by the transaction, interest eing reckoned at 6% ? 652.86

48. If a man borrow $15000 in New York, and lend it in hio, how much will he lose in 1 yr. and a half, reckoning 360 ays to the year in the former transaction, and 365 days in the itter? 206.507.

49. Hubbard & Northrop bought bills of dry goods of Bowen, McNamee & Co., New York, as follows, viz.: July 15, 1860, 1250; Oct. 4, 1860, $3540.84; Dec. 1, 1860, $575; and Jan. 24, 1861, $816.90. They bought on time, paying legal interest; how much was the whole amount of their indebtedness, March 1, 1861? 6354.818÷

50. A broker allows 6 per cent. per annum on all moneys deposited with him. If on an average he lend out every $100 received on deposit 11 times during the year, for 33 days each time at 2% a month, how much does he gain by interest on $1000? Ans. $182.

51. A man, engaged in business with a capital of $21840, is making 12 per cent. per annum on his capital; but on account of ill health he quits his business, and loans his money at 73 %. How much does he lose in 2 yr. 5 mo. 10 da. by the change? Ans. $2535.86%.

52. A speculator wishing to purchase a tract of land containing 450 acres at $27.50 an acre, borrows the money at 51⁄2 per cent. At the end of 4 yr. 11 mo. 20 da. he sells of the land at $34 an lose and the remainder at $32.55 an acre. How much does he by the transaction?

53. Bought 4500 bushels of wheat at $1.123 a bushel, payable in 4 months; I immediately realized for it $1.06 a bushel, cash, and put the money at interest at 10 per cent. At the end of 6 months I paid for the wheat; did I gain or lose by the transaction, and how much?

PARTIAL PAYMENTS OR INDORSEMENTS.

541. A Partial Payment is payment in part of a note, bond, or other obligation

542. An Indorsement is an acknowledgment written on the back of an obligation, stating the time and amount of a partial payment made on the obligation.

543. To secure uniformity in the method of computing interest where partial payments have been made, the Supreme Court of the United States has decided that,

I. "The rule for casting interest when partial payments have been made, is to apply the payment, in the first place, to the discharge of the interest then due.

II. "If the payment exceeds the interest the surplus goes towards discharging the principal, and the subsequent interest is to be computed on the baiance of the principal remaining due.

III. "If the payment be less than the interest the surplus of the interest must be taken to augment the principal, but the interest continues on the former principal until the period when the payments, taken together, exceed the interest due, and then the surplus is to be applied towards discharging the principal, and the interest is to be computed on the balance as aforesaid."-Decision of Chancellor Kent.

This decision has been adopted by nearly all the States of the Union, the only prominent exceptions being Connecticut, Vermont, and New Hampshire. We therefore present the method prescribed by this decision as the

UNITED STATES RULE.

I. Find the amount of the given principal to the time of the first payment, and if this payment exceed the interest then due, subtract it from the amount obtained, and treat the remainder as a new principal.

II. But if the interest be greater than any payment, compute the interest on the same principal to a time when the sum of the payments shall equal or exceed the interest due, and subtract the