The scales of commerce and trade: ballancing betwixt the buyer and seller, artificer and manufacture, debitor and creditor, the most general questions, artificiall rules, and usefull conclusions incident to traffique: comprehended in two books. The first states the ponderates to equity and custome, all usuall rules, legall bargains and contracts, in wholesale ot [sic] retaile, with factorage, returnes, and exchanges of forraign coyn, of interest-money, both simple and compounded, with solutions from naturall and artificiall arithmetick. The second book treats of geometricall problems and arithmeticall solutions, in dimensions of lines, superficies and bodies, both solid and concave, viz. land, wainscot, hangings, board, timber, stone, gaging of casks, military propositions, merchants accounts by debitor and creditor; architectonice, or the art of building. / By Thomas Willsford Gent.

PROPOSITION VI.

The price of any Wares or Merchandize by which the said Commodity was bought and sold: what gain was made, or loss sustained in the 100 lb: or after what rate or proportion.

The RULE.

As the price (by which any Merchandize was bought) shall be in value or proportion unto 100 lb sterling, so will the price of the Wares by which they were sold, be in proportion to the true gain or losse sustained.

An Explanation of Gain or Loss sustained, at any rate per Cent. Lib. 2. Parag. 8.

A Draper bought Kerseys 〈 math 〉〈 math 〉 at 6 lb. 13 ss. 4 d. the Peece, and sold them all a∣gain for 7 lb. 10 ss. how much he gained, and after what rate in the 100 lb

is the thing required: the price by which 'twas bought, and likewise the rate at which 'twas sold must be reduced into one denomination, or by the Rule of Fractions, viz. As 20/3 lb the price is to 100 lb, so 15/2 unto 112 ½: by which it is apparent that he gained 12 lb, 10 ss. in the 100 l. or after that rate; for 100 l. thus imployed will return 112 ½ l.

If any question of this kinde should depend up∣on Losse, the Price at which 'twas sold must be less then that by which the Commodity was bought at, so the fourth proportional number will be discover∣ed by the same Rule; the state of the Question not differing in any thing, either by Whole-sale, or Re∣tail, so it requires no Precedent or Rule but this, which will bring your stock short home, as unfor∣tunately true, as prosperously with increase.