strength and reducing friction. For decked vessels Shuldham proposed a revolving keel of lead, which, of course, was to be lowered and raised by a purchase attached to the after-end. At that time it does not appear that any vessel constructed in Europe was fitted with the revolving keel.
In 1811 Jacocks Swain, Henry Swain, and Joshua Swain, of Cape May, N.J., applied for and received a patent for the centre-board, or, as they called it, "a lee board through the bottom." The following are the official papers relating to the matter:
"THE UNITED STATES OF AMERICA.
"To all to whom these Letters Patent shall come:
"Whereas, Jacocks Swain, Henry Swain and Joshua Swain, citizens of the United States, have alleged that they have invented a new and useful improvement in the lee board, which improvement they state has not been known or used before their application, and have affirmed that they do verily believe that they are the true inventors or discoverers of said improvement, have paid into the Treasury of the United States the sum of $30, delivered a receipt for the same, and presented a petition to the Secretary of State signifying a desire of obtaining an exclusive property in the said improvement and praying that a patent may be granted for that purpose.
"These are therefore to grant according to law, to the said Jacocks Swain, Henry Swain and Joshua Swain, their heirs, administrators or assigns for the terms of fourteen years from the tenth day of
