In the same paper, Alexander Daggett advertises "for sale a negro man, _a first-rate blacksmith_." In the "Richmond Whig" of Jan. 25, 1848, Benjamin Davis advertises for sale a negro man "who is a first-rate carpenter by trade; also a rough blacksmith." In the "Charleston (S.C.) Mercury," Thomas W. Mordecai, broker and auctioneer, under date Sept. 1, 1847, advertises at private sale-- "An uncommonly prime and likely black man, about 22. A _prime woman_, a superior washer, and good cook and farm hand. A very prime axeman and field hand. A superior man-cook." It is not, however, necessary to teach a slave-mechanic or field hand, or even "a prime woman," to read or write, in order to make him or her a profitable investment. If we suppose William Craft's value as a slave to have been two thousand dollars, his master received from his investment _only_ twelve per cent _clear profit_! Yet William could neither read nor write. He was a valuable working machine. To have him educated farther, to have taught him to read or write, would have lessened his market value. To teach a slave these things is to teach him his rights, and to make him keenly feel his wrongs. Mrs. Hugh Auld taught Frederick Douglass his letters before slavery had hardened her naturally kind heart. She gave him the inch, as he says, and no precaution could prevent his taking the ell. He taught himself to read and write, and thus describes the effect produced by reading a book called "The Columbian Orator." This book contains one or more of Sheridan's speeches, and a dialogue between a master and his slave, wherein the slave is made to refute all the arguments usually brought forward in support of slavery. "The more I read," he says ("Narrative," p. 40), "the more I was led to abhor and detest my enslavers. I could regard them in no other light than a band of successful robbers, who had left their homes, and gone to Africa, and stolen us from our homes, and in a strange land reduced us to slavery. I loathed them as being the meanest as well as the most wicked of men. As I read and contemplated the subject, behold! that very discontentment which Master Hugh had predicted would follow my learning to read had already come, to torment and sting my soul to unutterable anguish. As I writhed under it, I could at times feel that learning to read had been a curse, rather than a blessing. It had given me a view of my wretched condition, without the remedy. It opened my eyes to the horrible pit, but to no ladder upon which to get out. In moments of agony, I envied my fellow-slaves for their stupidity. I have often wished myself a beast. I preferred the condition of the meanest reptile to my own,--any thing, no matter what, to get rid of thinking! It was this everlasting thinking of my condition that tormented me. There was no getting rid of it."