FOUND AT LAST. – A great discovery has just been made – as great as that of the mariner’s compass, the invention of printing, or of the man who struck Billy Patterson. Mr. Letcher, M. C. from Virginia, has just found out the man “[vot?] never reads” the NEW YORK HERALD. It is Mr. Clay, a member of Congress from Kentucky, who naively acknowledges the corn. Such a man ought to be the KNOW NOTHING candidate for the Presidency, and we so nominate him for 1860.