Ironworks (Iron & Steel)
John Robertson was shown as a partner [without dates] in Smith & Mitchell, Old Country Houses of the Old Country Gentry
Ironworking firm in Glasgow, founded c. 1732 [Smith & Mitchell give 1734], by 'colonial merchants', and shipping much of its output to Virginia in its early years.
Stuart Nisbet, The Slit Mill http://www.fork.org.uk/the-lost-mills-of-the-kelvin/the-slit-mill [accessed 14/09/2015].