U.S. Patent Office.

The U.S. Patent Office.

U.S. Patent Office.

The U.S. Patent Office.

Washington, D.C., Patent Office.

The U.S. Patent Office.

U.S. Patent Office.

U.S. Patent Office, Washington, D.C.

Interior, Patent Office.

U.S. Patent Office, Washington, D.C.

U.S. Patent Office.

U.S. Patent Office, Washington, D.C..

New Wing, Patent Office, Washington, D.C., U.S.A.

Interior of Patent Office, Washington, D.C., U.S.A.

Interior of Patent Office, Washington, D.C..

Model Room, in the U.S. Patent Office.

U.S. Patent Office, Washington, D.C..

U.S. Patent Office, Washington, D.C..

U.S. Patent Office, Washington, D.C., after the Doric Style of Architecture.

U.S. Patent Office, Washington, D.C. after the Doric Style of Architecture.

The U.S. Patent Office.

The U.S. Patent Office.

The U.S. Patent Office.

The U.S. Patent Office.

The U.S. Patent Office.

U.S. Patent Office.

U.S. Patent Office.

U.S. Patent Office, Washington, D.C.

The U.S. Patent Office.

The U.S. Patent Office.