A. _The number and extent of such commercial transactions as are effected by means of money_;(746) a relation which, evidently, increases (see § 56, ff.) with every advance in the division of labor. Hence the transition from serfdom and socage service to free labor, from domestic-servant labor to day-labor and piece-work, from feudal military service to that of paid and standing armies, from land-privileges and allowances in produce, such as fire-bote etc., to the payment of officials in money, from dues in produce to taxes in money, and regular lease-hold interests, from requisitions to loans of money; in a word, from the barter-economy (_Naturalwirthschaft_) of the middle ages to the trade by means of money in the higher stages of civilization, that is, from the “feudal” to the “commercial” system must, of itself, increase the money-need (_Geldbedarf_) of a people. B. _The rapidity of the circulation of money_; because, in most commercial transactions, one dollar which circulates ten times a year really performs the same service as ten dollars which go from hand to hand once in a year; just as the economic use of a ship employed in the transportation of commodities does not depend on its commodiousness alone but on its rapidity also.(747) The economic use of money does not depend on its amount simply. Says _Sismondi_: “The amount of the medium of circulation in a state must be equal to the sum of the payments made in it in a given time, divided by the sum of the times the former has, on an average, changed owners within that time.”(748) Under given economic circumstances, the rapidity of the medium of circulation is, taken all in all, not by any means an arbitrary matter. It will happen very seldom that one man will purchase or consume a commodity in order that another may not want money.(749) Were the greater number of money-earners (and in nations with a healthy economic life this number is always made up of men noted for the good management of their own affairs) inclined to pay out the money which they had taken in, rapidly, a very active production would prevail everywhere; and this, in turn, supposes general commercial freedom and great legal security. The less these conditions are developed, the more difficult it becomes, not only to lay out the money received to-day productively to-morrow, but the more imperatively does a proper foresight demand, that a reserve-fund should be maintained for times of necessity. (See § 43.)(750) Even in the same age and among the same people, money moves most slowly under the influences of troublesome and critical epochs; for the dangers of war and sedition, of impending burdensome taxation, commercial gluts and numerous cases of bankruptcy uniformly operate to make the possessors of money hold anxiously to their present supply.(751)