A new Volume of the SCIENTIFIC AMERICAN commences about the middle of September in each year. It is a journal of Scientific, Mechanical, and other improvements ; the advocate of industry in all its various branches. It is published weekly in a form suitable for binding, and constitutes, at the end ofeach year, a splendid volume of over 400 pages, with a copious index, and from five to six hundred original engravings, together with a great amount of practical information concerning the progress of invention and discovery throughout the world. The Scientific American is the most widely circulated and popular journal of the kind now published. Its Editors, Contributors, and Correspondents are among the ablest practical scientific men in the world. The Paten.t Claims are published weekly and are invaluable to Inventors and Patentees. PRIZES—We solicit attention to the splendid Prizes offered for the largest number of subscribers, consisting of a SILVER PITCHER worth $60 ; a set of the ICONOGRAPHIC ENCYCLOPEDIA worth $35 ; DEMPSEY'S MACHINERY OF THE NINETEENTH CENTURY, and C. B. Stuart's great work upon the NAVAL DRY DOCKS OF THE UNITED STATES. Letters should be directed (post-paid) to MUNN& CO., 128 Fulton street, New York. Terms ! Terms ! Terms ! One copy, for One Year$2 Six Months$1 Five copies, for Six Months$4 Ten Oopies for Six Months for$8 Ten Copies for.Twelve Months,$15 Fifteen Copies for Twelve Months, $22 Twenty Copies for Twelve Months, $28 Southern and Western Money taken at par for subscriptions, or Post' Office Stamps taken at their fall value.