THE present Number closes the Third Year and the Sixth Volume of HARPER'S NEW MONTHLY MAGAZINE. It has now reached a monthly edition of ONE HUNDRED AND EIGHTEEN THOUSAND copies and the demand for it is still increasing with greater rapidity than ever. This unparalleled and unexpected success has compelled the Publishers to resort to extraordinary means for printing the work with the requisite rapidity, and at the same time preserving the typographical elegance by which it has always been distinguished. It is now electrotyped by a new process, which makes it easy to print any number of copies from the same plates without in the least impairing the clearness and beauty of the impression. The Publishers desire to repeat their cordial acknowledgments to the Press and the Public, for the extraordinary favor which has thus far attended their efforts to interest and instruct the great body of the American people; and to renew their assurances that every possible effort will be made to increase still further the claims of their Magazine upon public favor and support. It will continue to present, at the cheapest price, the most interesting and instructive literary matter, original and selected, domestic and foreign, in the most elegant and convenient style, and accompanied by the finest pictorial illustrations, which a lavish expenditure of money can command. They appeal with confidence to the past, as a guarantee that their promises for the future will be abundantly fulfilled.