Uncle Tom.—We understand that the publisher continues to print ten thousand copies per week of "Uncle Tom's Cabin," without being able to overtake the demand. It is said, that when the work first appeared, a copy was purchased for the Mercantile Library in this city; that soon the demand became so eager that thirty copies were procured, and these not sufficing, fifteen more were added, making 45 copies circulating among those who are to be the successors of the Castle Garden Committee—the future merchants of New York. The devotees of southern trade who are not already bankrupt, had better raise a fund and circulate a sermon or something else, to head off Uncle Tom, or he will play the mischief with their arrangements.