Iron Act

The Act contained several provisions, applying from 24 June 1750:

• Duty on the import of pig iron from America should cease.
• Duty on bar iron imported to London should cease.
• Such bar iron might be carried coastwise or by land from there to Royal Navy dockyards, but otherwise not beyond 10 miles from London.
• The iron must be marked with its place of origin (most, if not all, pig iron was already marked).
• No mill or engine for slitting or rolling iron or any plating forge to work with a tilt hammer or any furnace for making steel should be erected in America.
• Colonial governors were required to certify what mills of these types already existed.

The limitation of imported bar iron to London and the dockyards was partly repealed in 1757 by 30 Geo. II c.16, duty-free imports to any part of Great Britain being permitted. A clause requiring bar iron to be marked was similarly repealed as unnecessary. A part of the act was also repealed by the American dominions (Trade with) Act 1765, (5 Geo. III c.45). The whole Act was repealed by the Statute Law Revision Act 1867, due to the replacement of colonial rule with the Dominion of Canada.

Pig iron had been exported from Virginia and Maryland since the 1720s, but little came from other colonies, nor did bar iron. The continuance of this was encouraged, as was the production and export of bar iron (which required a finery forge using a helve hammer not a trip hammer).

Conversely, the Act was designed to restrict the colonial manufacture of finished iron products and steel. Existing works could continue in operation, but no expansion would be possible in the output of:

• knives, scythes, sickles and other edged tools as a tilt hammer would be needed to produce thin iron, and a steel furnace to make steel.
• nails which were made from rod iron, from a slitting mill.
• Tinplate, which required a rolling mill. This was the raw material from which tinsmiths made a wide variety of goods from tinned sheet iron.

This was a continuation of a long term British policy, beginning with the British Navigation Acts, which were designed to direct most American trade to England (from 1707, Great Britain), and to encourage the manufacture of goods for export to the colonies in Britain.

The Iron Act, if enforced, would have severely limited the emerging iron manufacturing industry in the colonies. However, as with other trade legislation, enforcement was poor because no one had any significant incentive to ensure compliance. Nevertheless, this was one of a number of measures restrictive on the trade of British Colonies in North America that were one of the causes of the American Revolution.

Part of the reason for lax enforcement may be due to the involvement of Colonial Officials in iron works. Virginia Governors Gooch and Spotswood were both deeply involved in iron manufacture. Gooch was a part owner of the Fredericksville Ironworks. Spotswood owned Tubal Ironworks (a blast furnace and probably finery forge) and the double air furnace at Massaponnax. Other prominent members of the Virginia aristocracy and House of Burgesses involved in the iron industry included John Tayloe (Bristol Ironworks, near Fredericksburg; Neabsco Ironworks; and Occoquan Ironworks), Augustine Washington, George's father (Accoceek/Potomac Ironworks), and Benjamin Grimes (Grimes Recovery and a bloomery near Fredericksburg).

• Bining, A. C. (1933). British Regulation of the Colonial Iron Trade. Philadelphia: Univ. of Philadelphia Press. OCLC 2013136.

• Contemporary debate on the Iron Act
• Green Castle Museum website
• Text of the Iron Act