Nevertheless, Pennsylvania did in a few cases lay low protective duties. Except for the sea-faring pursuits of the Northern colonies, the whole continental group was in the same dependent condition. The colonists raised their own food and made their own clothes; the surplus of their crops was sent abroad and converted into manufactured goods. 10. COLONIAL SLAVERY. [Sidenote: Slave trade.] [Sidenote: The sections.] In appearance the labor system of all the colonies was the same. Besides paid white laborers, there was everywhere a class of white servants bound without wages for a term of years, and a more miserable class of negro slaves. From Nova Scotia to Georgia, in all the West Indies, in the neighboring French and Spanish colonies, negro slavery was in 1750 lawful, and appeared to flourish. Many attempts had been made by colonial legislatures to cut off or to tax the importation of slaves. Sometimes they feared the growing number of negroes, sometimes they desired more revenue. The legislators do not appear to have been moved by moral objections to slavery. Nevertheless, there was a striking difference between the sections with regard to slavery. In all the colonies north of Maryland the winters were so cold as to interfere with farming, and some different winter work had to be provided. For such variations of labor, slaves are not well fitted; hence there were but two regions in the North where slaves were profitably employed as field-hands,--on Narragansett Bay and on the Hudson: elsewhere the negroes were house or body servants, and slaves were rather an evidence of the master's consequence than of their value in agriculture. In the South, where land could be worked during a larger portion of the year, and where the conditions of life were easier, slavery was profitable, and the large plantations could not be kept up without fresh importations. Hence, if any force could be brought to bear against negro slavery it would easily affect the North, and would be resisted by the South; in the middle colonies the struggle might be long; but even there slavery was not of sufficient value to make it permanent. [Sidenote: Anti-slavery agitation.]