The more northerly colonies had no such natural advantages. The bulk of the population lived by ordinary farming, grew wheat and the hard cereals and raised cattle. But during the eighteenth century England herself was still an exporting country as regards these commodities, and with other nations the colonists were forbidden to trade. The Northern colonies had, therefore, no considerable export commerce, but on the seaboard they gradually built up a considerable trade as carriers, and Boston and New York merchant captains began to have a name on the Atlantic for skill and enterprise. Much of the transoceanic trade passed into their hands, and especially one most profitable if not very honourable trade of which, by the Treaty of Utrecht, England had obtained a virtual monopoly--the trade in Negro slaves. The pioneer of this traffic had been Sir John Hawkins, one of the boldest of the great Elizabethan sailors. He seems to have been the first of the merchant adventurers to realize that it might prove profitable to kidnap Negroes from the West Coast of Africa and sell them into slavery in the American colonies. The cultivation of cotton and tobacco in the Southern plantations, as of sugar in the West Indies, offered a considerable demand for labour of a type suitable to the Negro. The attempt to compel the native Indians to such labour had failed; the Negro proved more tractable. By the time with which we are dealing the whole industry of the Southern colonies already rested upon servile coloured labour. In the Northern colonies--that is, those north of Maryland--the Negro slave existed, but only casually, and, as it were, as a sort of accident. Slavery was legal in all the colonies--even in Pennsylvania, whose great founder had been almost alone in that age in disapproving of it. As for the New England Puritans, they had from the first been quite enthusiastic about the traffic, in which indeed they were deeply interested as middle-men; and Calvinist ministers of the purest orthodoxy held services of thanksgiving to God for cargoes of poor barbarians rescued from the darkness of heathendom and brought (though forcibly) into the gospel light. But though the Northerners had no more scruple about Slavery than the Southerners, they had far less practical use for it. The Negro was of no value for the sort of labour in which the New Englanders engaged; he died of it in the cold climate. Negro slaves there were in all the Northern States, but mostly employed as domestic servants or in casual occupations. They were a luxury, not a necessity.