THATletters patent granted to Oliver C. Harris on the fifteenth day of March, eighteen hundred and thirty two, for his improvement in paint mills, or manner of grinding paints, indigo, &c., &c., be, and the same are hereby, extended for the term of seven years from and after the passage of this act; and the Commissioner of Patents is hereby directed to renew and extend said patent by making certificate thereon, or upon a certified copy thereof of such extension; and the Commissioner is hereby directed, to cause the same to be entered on record in the Patent Office, and the said patent so extended shall have the same effect in law as if originally granted for twenty one years, in the form herein provided.