The building has two stories. Shown are the first windows beside the projecting central parts. Steps lead up to te door in the first story. It is flanked by embedded columns. In the second ring are two pilasters at left and at right of the central opening. Above the entablature is a probably octagonal story of the tower with an oening framed by an aedicula at the front. The uppermost story is circular, with embedded columns supporting the entablature. A dial supported by two figures is at the front. Many measurements are indicated. At right is an accounting. Colored background. Pen and brown ink, brush and brown wash on lined off-white laid paper. Date: 1746-1809. Museum: Cooper Hewitt, Smithsonian Design Museum.