Under the Restoration the Commonwealth law was confirmed and extended (1660). Such enumerated colonial products as the English merchants desired to purchase were to be shipped to no other country than England; but those products which they did not wish might be sent to other markets, provided they did not there interfere in any way with English trade. In all transactions, however, "English-built ships," manned by "English subjects" only, were to be patronized. Three years later (1663) another step was taken. By an Act of that year, such duties were levied as amounted to prohibition of the importation of goods into the colonies except such as had been actually shipped from an English port; thus the colonists were forced to go to England for their supplies,--the mother-country making herself the factor between her colonies and foreign markets. Sidenote: Repression of intercolonial trade. A considerable traffic had now sprung up between the colonies. New England merchants were competing with Englishmen in the Southern markets. At the behest of commercial interests in the parent isle, an Act was passed in 1673 seriously crippling this intercolonial trade; all commodities that could have been supplied from England were now subjected to a duty equivalent to that imposed on their consumption in England. From 1651 to 1764 upwards of twenty-five Acts of Parliament were passed for the regulation of traffic between England and her colonies. Each succeeding ministry felt it necessary to adopt some new scheme for monopolizing colonial trade in order to purchase popularity at home. It was 1731 before the home government began to repress the manufacture in the colonies of goods that could be made in England; thereafter numerous Acts were passed by Parliament having this end in view. Sidenotes: England's coercive commercial policy a cause of the Revolution. In brief, the mother-country regarded her American colonies merely as feeders to her trade, consumers of her manufactures, and factories for the distribution of her capital. Parliament never succeeded in satisfying the greed of English merchants, while in America it was thought to be doing too much. The constant irritation felt in the colonies over the gradual application of commercial thumb-screws--turned at last beyond the point of endurance--was one of the chief causes of the Revolution. Had it not been that colonial ingenuity found frequent opportunities for evading these Acts of Navigation and Trade, the final collision would doubtless have occurred at a much earlier period. 45. Social Life. Sidenote: Travel and roads.