The panic of 1837 caused a falling off in the domestic slave trade, and the low price of cotton which continued until 1846[155] hindered its revival. The falling off in the trade is shown by the fact that the per cent. of increase in the slave population of the cotton States was scarcely half as great between 1840 and 1850 as during the previous decade.[156] The slave trade, however, seems to have become brisker in 1843, for while only 2,000 slaves are said to have been sold in Washington in 1842, in 1843, 5,000 were sold there.[157] It does not necessarily follow, however, that all these were sent South. The increased number of sales was caused by two things: the decline in the price of tobacco,[158] and the renewed activity in the sugar industry incident upon a new duty on sugar.[159] This gave rise to a demand for slave labor upon the sugar plantations of the South, but it was a very limited demand. During this period the decline in the value of slaves was great in some States,[160] and it appears very probable there was a general depreciation in value. However, before 1850 three important things had happened, each of which had an effect upon the slave trade. First, the admission of Texas, December, 1845; second, the gradual increase in the price of cotton after 1845; third, the discovery of gold in California. The first opened a large cotton country to development and the required slave labor could be legally supplied only from the United States. The rise in cotton which continued almost uniformly until 1860[161] caused a new impetus to be given to its culture, and the discovery of gold in California infused new life into all the channels of trade.
In a few years, indeed, after 1845, the demand for slaves seems to have been greater than the supply. A writer in the "Richmond Examiner," in 1849, says:
"It being a well ascertained fact that Virginia and Maryland will not be able to supply the great demand for negroes which will be wanted in the South this fall and next spring, we would advise all who are compelled to dispose of them in this market to defer selling until the sales of the present crop of cotton can be realized as the price then must be very high owing to two reasons: First, the ravages of the cholera, and secondly, the high price of cotton."[162]
Indeed, during the fifteen years prior to 1860 the demand for slaves became so great that it caused an increase of one hundred per cent. in their price.[163] However, there was not a great increase in the domestic slave trade. According to a custom house report there were shipped from Baltimore in a little less than two years, in 1851 and 1852 only 1,033 negroes.[164] This is certainly not a large showing though it is probable a great many were sent overland to the South from this place during the same time.
In a speech before the Southern Convention at Savannah in 1856, Mr. Scott, of Virginia, made the statement that not more than half the lands in the sugar and cotton-growing States had been reduced to cultivation, and that all the valuable slaves in Virginia, Maryland, Kentucky and Missouri would be required to develop them.[165] But at this time the prosperity of the latter militated against the transfer of labor to the cotton-growing States. Probably the conditions in the border States is best described by quoting from a writer in "De Bow's Review" in 1857:
"The difficulty," he says, "of procuring slaves at reasonable rates, has already been severely felt by the cotton planters, and this difficulty is constantly increasing. The production of rice, tobacco, wheat, Indian corn, etc., with stock raising, in those States affords nearly as profitable employment for slave labor as cotton planting in other States. They have not, as is generally supposed, a redundancy of slave labor, nor are they likely to have so long as their present prosperity continues.
"The recent full development of the rich agricultural and mineral resources of these States, indeed, by an immense demand for their staple productions, have not only given profitable employment to slave labor, but has improved the pecuniary condition of the slave owner and placed him above the necessity of parting with his slave property."[166]
Even Olmsted, inadvertently, no doubt, gives evidence of the prosperity of Virginia, a little before this time, when he says that in the tobacco factories of Richmond and Petersburg slaves were in great demand and received a hundred and fifty to two hundred dollars and expenses a year.[167] In North Carolina, also, good hands would bring about the same wages.[168]
Though the labor market in the border States was greater than the natural increase of the negro, yet it was hardly to be compared to the Southern demand. As a consequence, when debt, or necessity, or other reason, compelled the sale of slaves, they were often bought by traders and exported.[169] The statement was made by Mr. Jones, of Georgia, in the Savannah Convention, 1856, that negroes were even then worth from $1,000 to $1,500 each, and that there were ten purchasers to one seller.[170]