The blacksmith shop is a classic example of nineteenth-century industrial building type. The long, narrow structure makes efficient use of the line shaft along its long south wall, while its tight width permits ample lighting and ventilation through the large sash windows with splayed jambs along the walls. The wooden trussed roof allows for an open, flexible plan without internal supports, and its monitor roof provides additional lighting and ventilation. Openings for the line shaft are visible in each end wall and rectangular yellow patches of sulfur grouting reveal the locations of its bearing foundations. The shop housed seven forges along the walls that were naturally vented into the floor through a remarkable system of underground conduits to the smokestack; the foundation of one forge is still visible in the floor. Iron and steel heated in the forges were handled by jib cranes, one of which survives, and worked by a ten-ton steam hammer. The present operational example, which is not the original, was installed in 1996. Rough forgings from the blacksmith shop were finished in the machine shop (1855; 1878 rebuilt with additional story and modified roof; 1979 collapsed), now in ruins abutting the east wall. From there, the completed parts could be installed in the adjacent roundhouse (7.1.7).