"The introduction of slavery into this country, is, at this day, considered among its _greatest misfortunes_." And in 1803, he said, after pronouncing slavery to be "a calamity, a reproach, and a curse,"--"those who wish to postpone emancipation, do not reflect that every day renders the task more arduous to be performed." General Harper says,-- "It tends, and may powerfully tend, to rid us gradually and _entirely_ in the United States, _of slaves and slavery_, a great _moral and political evil, of increasing virulence and extent_, from which much mischief is now felt, and very great calamity in future, is justly apprehended. It speaks not only to our understandings, but to our senses; and however it may be derided by some, or overlooked by others, who have not the ability or time, or do not give themselves the trouble to reflect on, and estimate properly, the force and extent of those great moral and physical causes, which prepare gradually, and at length bring forth the most terrible convulsions in civil society; it will not be viewed without deep and awful apprehensions by any who shall bring sound minds, and some share of political knowledge and sagacity, to the serious consideration of the subject. Such persons will give their most serious attention to any proposition which has for its object, the eradication of this terrible mischief lurking in our vitals."--_Letter on Colonization Society._ Darby says,-- "Copying from Montesquieu, and not from observation of nature, climate has been called upon to account for stains on the human character, imprinted by the hand of political mistake. No country where negro slavery is established, but must bear, in part, the wounds inflicted on nature and justice. Without pursuing a train of metaphysical reasoning, we may at once draw this induction, that if slavery, like pain, is one of the laws of existence, the latter does not more certainly produce physical weakness, debility, and death, than does the former lessen the purity of virtue in the human breast."--_History of Louisiana._ M'Call says,-- "It is shocking to human nature, that any race of mankind, and their posterity, should be sentenced to perpetual slavery." _History of Georgia._ General Mercer says,--