The Lucky have whole Days

I, like your correspondent "P.S." (No. 15., p. 231.), am anxious to ascertain the authorship of the lines to which he refers. They stand in my Common-place Book as follows, which I consider to be a more correct version than that given by "P.S.":— "Fate's dark recesses we can never find, But Fortune, at some hours, to all is kind: The lucky have whole days, which still they choose; The unlucky have but hours, and those they lose."