Uncle Tom's Cabin.—We are informed by Messrs. Jewett & Company, the publishers of the above thrilling work, that they are now printing the Fiftieth thousand copies, making One Hundred thousand volumes issued in eight weeks! This is without a precedent in the history of book publishing in this country. The demand continues without abatement. Our readers can judge of the labor of producing so great a number of books in so short a time when informed that it has taken 3000 reams of medium paper, weighing 30 lbs. to the ream—90,000 lbs. of paper; and that three or four of Adams's power presses have been kept running at the most rapid rate, day and night, stopping only on the Sabbath; and that from 125 to 200 bookbinders have been constantly at work in binding. Weight of books when bound about 110,000 lbs. or 55 tons. These have been principally transported in small boxes or packages by Messrs. Kinleys & Co. and Thompson & Co.'s Expresses. What could have been done towards transporting so large a number of packages in so short a time, only a few years since?