Between 1810 and 1820 slaves in the four States of Georgia, Mississippi, Tennessee and Louisiana in round numbers increased from 202,000 to 332,000,[117] and in some of the other States the increase was about as great. During the same time the white population in the States named increased from 419,000 to 645,000.[118] By far the greater part of this increase took place after 1815. To prove this we will take Louisiana as an example. In 1810 she had a population of 76,500,[119] and in 1815 near the close of the year her population, according to Monette, did not exceed 90,000,[120] an increase of only 12,000; but in 1820 it amounted to 154,000, of which more than 73,000 were negro slaves.[121] It appears that the slaves in Louisiana increased only about 2,000 or 2,500 from 1810 to 1815, but between 1815 and 1820 there was an increase of about 37,000.[122] This wonderful increase in population in the West and Southwest is to be accounted for by the fact that after the close of the War of 1812 immigration again set in these directions, and, as most of the immigrants without doubt were from the older Southern States, they carried with them the slaves which they had in their native States.[123] Another source from which this region received slaves at this time was through the operation of the illicit foreign trade. It is probable that 10,000 or 15,000 a year were thus introduced.[124] It therefore seems that up to this time to the domestic trade is due probably only a minor part of the increase of the slave population of this section. During the twenties, however, if we are to give credit to the statements of travellers, the trade reached very great proportions. Baltimore, Norfolk, Richmond, Washington and other places had already become centres. Agents were placed in these cities to attend to purchase and shipment. "And thousands and tens of thousands," such is the language of an English tourist, were purchased in Virginia and Maryland for sale in Georgia, Louisiana and other States.[125] Blane, another Englishman, who visited the United States about the same time, is more to the point. "It is computed," he says, "that every year from ten to fifteen thousand slaves are sold from the States of Delaware, Maryland and Virginia and sent to the South."[126] Basil Hall was informed, in 1827 or 1828, that during certain seasons of the year, "all the roads, steamboats and packets are crowded with troops of negroes on their way to the slave markets of the South.[127] Vessels, indeed, from the selling States were sometimes seen in New Orleans with as many as two hundred negroes aboard."[128]