eighteenth century. [Sidenote: Restrictions on commerce] The industrial and commercial life of the colonies suffered under restrictions quite as effective as those that burdened the cause of letters. Importation to the dependencies of South America was limited by positive laws, and the exportation of certain products was made practically impossible, because they could not successfully compete with similar commodities produced elsewhere, on account of the greater cost of transportation from the western ports of South America. Agriculture was limited by the prohibitory cost of transporting its products, and by the fact that the small population offered only a restricted demand for them, a demand that was insufficient to bring into cultivation the available fertile land or to employ the available labourers. This limited domestic demand and the impossibility of exporting the products constituted an effective restriction on agricultural progress; and this restriction was intensified by arbitrary governmental prohibition affecting certain branches of cultivation, notably wine and sugar. But mining for gold and silver was free from all restrictions, and the fact that the crown received one-fifth of the products was a reason for governmental encouragement of the industry. This freedom in the development of mining and the hindrances encountered by other forms of industry caused the population and the appliances of civilization to increase more rapidly in the mining regions, in the inhospitable high lands of Upper Peru, than in the fertile valleys of Chile or on the rich Argentine plains. Potosí, for instance, became a bustling city of 150,000 inhabitants before Buenos Aires and the towns of Chile had emerged from the condition of dirty frontier villages.[9] [Sidenote: The spiritual inheritance] [Sidenote: Mediævalism in the colonies]