"The rapidity with which books are now manufactured is almost incredible. A complete copy of one of Bulwer's novels, published across the water in three volumes, and reproduced here in one, was swept through the press in New-York in fifty hours, and offered for sale smoking hot in the streets. The fabulous edifice proposed by a Yankee from Vermont, no longer seems an impossibility. 'Build the establishment according to my plan,' said he; 'drive a sheep in at one end, and he shall immediately come out at the other, four quarters of lamb, a felt hat, a leather apron, and a quarto Bible.'" The business of the Messrs. Harper, whose establishment is referred to in the foregoing extract, is probably more generally diffused over every section of this country than that of any other publishing house. From enquiries recently made of them we learn that they issue, on an average, 3,000 bound volumes per day, throughout the year, and that each volume will average 500 pages--making a total of about one million of volumes, and not less than five hundred millions of pages per annum. This does not include the Magazine and books in pamphlet form, each of which contains as much matter as a bound volume.--Their bills for paper exceed $300,000 annually, and as the average cost is fifteen cents per pound, they consume more than two millions of pounds--say one thousand tons of white paper. There are regularly employed in their own premises about 550 persons, including printers, binders, engravers, and clerks. These are all paid in full once a fortnight in bankable money. Besides these, there are numerous authors and artists in every section of the country, who furnish manuscripts and illustrations, on terms generally satisfactory to all the parties interested. The Magazine has a monthly circulation of between 115,000 and 200,000, or about two millions of copies annually. Each number of the Magazine is closed up about the fifth of the month previous to its date. Three or four days thereafter the mailing begins, commencing with more distant subscribers, all of whom are supplied before any copies are sold for delivery in New-York. The intention of the publishers is, that it shall be delivered as nearly as possible on the same day in St. Louis, New-Orleans, Cincinnati, Philadelphia, Boston, and New-York. It takes from ten to twelve days to dispatch the whole edition, (which weighs between four and five tons,) by mail and express. Their new periodical, "Harpers' Weekly," has, in a little more than four months, reached a sale of nearly 70,000 copies. The mailing of this commences on Tuesday night, and occupies about three days.