in the old days of barter. For example, Collins would buy of Cox, a plantain cloth weaver, 5l. worth of cloth, and would give him a written promise to pay him five sovereigns at the end of four weeks; before the four weeks are over Mrs. Collins has made a complete suit of clothes for Cox and each of his four children; for which service Cox gives her a written promise to pay her five sovereigns in a fortnight's time. Now if Mr. and Mrs. Collins cancel Cox's debt to them, Cox agrees to cancel Collins's debt to him; so the cloth and the suits of clothes exchange for one another without the transfer of any money on either side, just as they would have done in the time when all exchanges were made by barter. It sometimes happened, of course, that two people were indebted to each other, but not for exactly the same amount. Thus Cox may have promised to pay the carpenter 1l., while the carpenter may have promised to pay Cox 18s. In this case, the balance, 2s., will have to be paid in money by Cox to the carpenter; but nevertheless it must be remembered that an amount of buying has taken
