The Virginians at first neither sought nor needed negro slaves; this is proven by the circumstances under which the first slaves were landed, and also by the fact that slavery grew very slowly. In 1622 there were only twenty-two negro slaves in the Colony, and in 1648, twenty-eight years after the first acquisition, there were only three hundred in Virginia; not that the settlers were averse to using them, but because another class of cheap labor was obtainable in the great number of criminals which were sent from England to work out their freedom in the New World, and by other white persons who voluntarily sold themselves and became indented or bond servants for a period of years in payment of their passage to America, or for other considerations. The use of this class of labor began very shortly after the first settlement, but toward the close of the seventeenth century the use of indented servants became less as negro slaves became more numerous. Negro slaves were introduced into every one of the other Colonies when they were founded, or a short time afterwards, and to the close of the Revolution negro slaves were used in every Colony. The North was for slavery as long as it was necessary and profitable, and the early settlers in New England found no scruple in using as slaves the Indians captured in war; and when negro slavery appeared later, the shrewd Yankees made money in the slave trade along the coast to the South and to the West Indies. The modern Newport, R. I., was the great slave mart of New England, and it is said that the first slave ship used by American colonists was fitted up in a New England port. Prior to 1715 the number of slaves in America was not so great, but after that year they increased in large numbers, not only by an active demand which sprang up for them, but also by the infamous Asiento Clause in the Treaty of Utrecht between England and Spain, whereby the former for a period of thirty years, from 1713 to 1743, took the exclusive right of importing and selling 144,000 negroes into the Spanish Colonies at the rate of 4,800 per year, and more could be brought in on the payment of a small tax. This made England the greatest slave nation in the world, and her interest demanded, and Parliament saw to it, that nothing adverse to the use of slaves should happen in the American Colonies. The growth of slavery in America from 1715 to 1775, and the slave population in the Colonies at these two periods, were as follows: