Before revision: Cast iron Columns made of cast iron were introduced in 1770s, the first building with multiple storeys using cast iron for both columns and beams is the Ditherington Flax Mill in Shrewsbury (1797).
After revision: Cast iron frame in Watervliet Arsenal building 40 ()Cast iron Columns made of cast iron were introduced in 1770s, the first building with multiple storeys using cast iron for both columns and beams is the Ditherington Flax Mill in Shrewsbury (1797).