A bank cannot, consistently with its own interest, advance to a trader the whole, or even the greater part of the circulating capital with which he trades; because, though that capital is continually returning to him in the shape of money, and going from him in the same shape, yet the whole of the returns is too distant from the whole of the outgoings, and the sum of his repayments could not equal the sum of his advances within such moderate periods of time as suit the conveniency of a bank.