If at an expense, it is sometimes called Premium. For illustration, under the 1st division; suppose A holds a note against B for $500 due in four months, and B comes to-day and proffers payment; the custom is, for A to deduct the interest on $500 for four months, from the face of the note; and to accept the balance as payment in full: thus considering the use of the remainder of the amount, sufficient to compensate for the deficiency in the payment of the face of the bill. But this is manifestly incorrect, if we take the existing law of this State, which declares the value of the money to be but six per cent. per annum, to be founded on just principles. For the interest on the remainder of the note, after deducting the interest on the face of the note therefrom, is not sufficient at the same rate per cent. to make up the original sum. So that B, by paying thus in advance, secures a larger rate of interest than is lawful. Yet this is the usage, and it is an old adage, and well established, that _usage makes law_. This is what is termed _Bank Discount_. _True Discount_, is such a sum, as, when deducted from the original debt, the interest on the balance will just equal the amount deducted. The method of ascertaining this is by proportion, or, as it is called in arithmetics, _rule of three_. Thus we would say, as the amount of $100. and interest for the given time and rate is to the interest on $100. for the same time and rate, so is the total sum to the amount of discount to be deducted therefrom. Stated thus,-- 102.00 : 2.00 :: 500.00 : the answer. 2d. If C sells goods to D and within a certain limited time, usually among the jobbing trade of our city 30 days after purchase, D pays for them in cash, usage again allows him a deduction from the face of the invoice of say 5 per cent. This is also _called_ Discount, but it is not properly such. For it is only a deduction of such a proportion or per centage of the bill, on fulfillment of certain conditions; while Discount is reckoned with reference to time to run, as well as rate per cent.; in fine, Discount is simple Interest paid beforehand. 3d. The term _Discount_ is also applied to that sum which is advanced beyond or deducted from the amount of a debt, in remitting money from one country to another.