114 Progress of Population and Wealth 



than China, the labour of grown slaves would generally be profit- 

 able ; and the barbarous policy of making slaves of prisoners of 

 war may continue slavery in some countries, as it does in Africa, 

 in which its profits could not keep up its own stock. But in the 

 United States, those who would appropriate to themselves the 

 labour of the adult slave, must consent to incur the previous charge 

 of his childhood. 



We must also bear in mind that the slaveholding States are 

 almost exclusively agricultural, and, consequently, that their popu- 

 lation is principally rural. Not over one-thirtieth of their popula- 

 tion, if we take away Baltimore and New Orleans, live in towns, and 

 with the inhabitants of those cities, not one-sixteenth part. In 

 densely peopled countries, however, from one-half to two-thirds live 

 in cities and towns; thus showing that from a third to a half of their 

 whole population is sufficient for their culture ; of course, were the 

 density as much as 120 to the square mile, from 40 to 60 persons 

 would be as many as could be advantageously employed on the 

 soil ; and thus the value of labour would decline as much and as 

 fast in a country that was purely agricultural, as it would in another 

 of twice its population that was also manufacturing. Should, then, 

 agriculture continue to be the principal occupation of the slavehold- 

 ing States, and they not betake themselves more extensively to 

 manufactures, the population, when it amounts to 50 persons to the 

 square mile, will have reached that point when every addition to it 

 will rapidly depreciate the value of labour. We may, therefore, 

 reasonably infer that, if its value in the slaveholding Slates should 

 not have attained the supposed point of depression when they have 

 a population of 50 to the square mile, they will attain it in no long 

 time afterwards. 



It affords some confirmation of these views, that when emanci- 

 pation took place in New Jersey, which probably has the average 

 fertility of the present slaveholding States, the population was 

 something less than 40 to the square mile, and that, even then, the 

 labour of slaves was thought not much to exceed the cost of their 

 subsistence ; and that many judicious slave-owners in Maryland 

 and eastern Virginia, where the population, exclusive of Baltimore, 

 scarcely exceeds 35 to the square mile, believe that the labour of 

 their slaves yields but a small net profit. 



Supposing, then, a density of 50 persons to the square mile to be 

 incompatible with the longer continuance of slavery in the States 

 now permitting it, their aggregate population would then amount to 



