Interior view of the machine shop at the Portland Company, Portland, Maine, ca. 1890. "This photograph shows...the machine shop, where small castings are being machined to high tolerances. In the foreground we see a pile of casting flasks used when cast parts are made by pouring molten metal into sand molds in the foundry." - Fletcher, David H. 'The Portland Company 1846-1982. Charleston, S.C. : Arcadia Pub., 2002. 15.