A Concise and Easy System of Book-keeping for Solicitors, &c. ..

A FEW USEFUL ARITHMETICAL AND TABULAR MEMORANDA.

33 1-3rd years-purchase of any annual sum gives 3 per cent. on the purchase money.

30 years purchase, 3 1-3rd per cent.

28 4-7th years purchase, 3 per cent. 25 years purchase, 4 per cent.

20 years purchase, 5 per cent.

16 2-3rd years purchase, 6 per cent.
14 2-7th years purchase, 7 per cent.
12 years purchase, 8 per cent.
11 1-9th years purchase, 9 per cent.
10 years purchase, 10 per cent.

To calculate the value of French funds.-Suppose the income to be 585 rentes per annum (4 per cents.). The principal requisite to produce that sum is 13,000 francs, the value of which, in French money, at 90 francs per cent., is 11,765 francs, the value of which, in English money, at 25 francs per pound sterling, is 4617. 7s. 5d.

To calculate interest.-Multiply the principal sum by the rate per cent. and divide by 100: the result is the interest for one year. When there is a broken number of days, take the fractional proportionate part, or parts, of a year's interest, or proceed by the rule of three.

[This mode of calculation, however, would only be useful in the absence of an "Interest Book."]

Weight, measure, and number.-In Troy weight, by which are weighed gold, silver, jewels, &c., there are 12 ounces to the pound. The like in Apothecaries weight. In Avoirdupois weight, (by which are weighed all such commodities as are coarse and drossy, or subject to waste, as groceries, bread, butter, cheese, tallow, &c., and likewise all metals, except gold and silver,) there are 16 ounces to the pound. A stone, horseman's weight, 14 lbs. The like of butchers' meat in London 8 lbs. 6 feet-one fathom. A cubit-1 foot. 5 yards-1 rod, pole, or perch. 4 poles, or 100 links-1 chain. 40 poles, or 10 chains-1 furlong. 8 furlongs, or 1760 yards-1 mile. 3 miles1 league. 60 geographical miles, or 69 1-10th English miles-1

degree. Square measure :-9 feet-1 yard; 30 yards-1 pole, rod, or perch; 40 perches-1 rood; 4 roods-1 acre. Wine measure:31 gallons-1 barrel, or half hogshead; 42 gallons-1 tierce; 63 gallons-1 hogshead; 84 gallons-1 puncheon; 2 hogsheads-1 pipe, or butt; 2 butts-1 tun. Beer measure:-9 gallons-1 firkin; 2 firkins-1 kilderkin; 36 gallons-1 barrel; 54 gallons-1 hogshead; 2 hogsheads-1 butt; 2 butts-1 tun. Dry measure:- -(for grain, fruit, &c.) 2 gallons-1 peck; 4 pecks-1 bushel; 4 bushels-1 coomb; 2 coombs-1 quarter; 4 quarters-1 chaldron; 5 quarters-1 wey; 2 weys-1 last. Number:-12 units-1 dozen; 12 dozen-1 gross; 12 gross-1 great gross; 20 units-1 score; 5 score-1 short hundred; 6 score-1 long hundred; 24 sheets-1 quire of paper; 20 quires-1 ream. India: A lac (or lakh)-100,000 rupees. French measure:-A metre-39 inches. French quantity:-A litre-35th part of a bushel. French weight:-A kilogram-2 2-3rd lbs. Troy.

TIME IN WHICH MONEY WILL DOUBLE ITSELF, AT SIMPLE AND COMPOUND YEARLY INTEREST.