Mode of Hanging the Sceeens in Winnowing Machines.—John a. Krake, of Alden, n. y., has petitioned for the extension ot the above patent. Day of hearing, November 8,1869. Machine foe Channeling stone.—John Taggart, of Melrose, Mass., has ipplied for an extension of the above patent. Day of hearing November 15.1869. How to ret Patents lExtended. Patents can be extended, for seven years.under the general law. but t is requisite that the petition for extension should be filed witli the Commissioner of Patents, at least ninety days before the date on winch he patent expires. Many patents are now allowed to expire which could be nade profitable under an extended term. Applications for extensions can mly be made by the patentee, or. in the event of his death, by his legal rep-esentative. Parties interested in patents about to expire, can obtain all iccessary instructions how to proceed, free of charge, by writing to MUNN & co., 37 Park Row. New York.