In 1827 or 1828 (the paper is watermarked 1827), William Symington produced a coloured drawing labelled “A Section of Blast Furnaces,” to illustrate an original mode of construction which he claimed would require only one third of the power which was then required to deliver the compressed air to the blast furnaces in common use. He dates the invention March, 1821. This drawing was one of a collection of illustrations which William Symington prepared in about 1828 and which were kept and brought to Australia in 1855 by his son William.

His drawing of the blast furnace tower depicts a tapering conical internal form as compared with a rounded goblet shaped contour; two configurations of blow pipe are depicted. He does not explain how it works. There is no explanatory text to reveal the essence of the claimed improvements but it seems that his intention was to increase the air flow to the furnace by means of a pressure jet.

William Symington had been well acquainted with the Carron Company blast furnaces. The blast furnaces at Carron comprised cylindrical chambers of plate iron, thickly lined with fire-brick and supported on cast iron columns. The interiors tapered inwards towards the hearth. ^[1]

In 1762 John Smeaton (1724-1792), consulting engineer to Carron Company had introduced the first piston-driven air pump at the Carron ironworks. The first blowing engines for the Carron blast furnaces were driven by a water wheel. Smeaton had a particular interest and expertise in the design and construction of water wheels and he designed the water wheel and a blowing engine for the Carron furnaces. In 1764 he submitted a design for blast furnace Number 1 at Carron; in 1769 he made recommendations for the water wheel. ^[2]

William Symington's concept was soon superceded by an impotrant advance, the invention of a hot blast technique which was patented by James Neilson in 1828. ^[3]

William Symington may have developed an interest in blast furnaces after providing an engine to Colonel Fullarton in 1793 to drive his "blowing machine". ^[4] Colonel Fullarton (1754-1808) of Fullarton, near Troon, was experimenting with blast furnaces in the production of wrought iron. ^{[5] [6]} He patented a method to obtain malleable bar iron from iron ore in a single process. ^[7]

Fullarton also had a link with Wanlockhead: his cousin, William Fullarton, had married Annabella Craufurd, a daughter of Ronald Craufurd, partner in the Wanlockhead Mining Company and sister of the Countess of Dumfries.

^[1] Watters, Brian, Where Iron Runs Like Water! A New History of Carron Iron Works 1759-1982 Edinburgh 1998

^[2] Royal Society, Smeaton Catalogues. Volume 2, Mills and Hydraulic Engines, Folios 66v, 67 and 68

^[3] Neilson, James Beaumont, Patent number 5701. Application of air to produce heat in fires, forges, or furnaces where bellows and other blowing-apparatus are required.

^[4] SRO GD58/1/29 Carron to Fullarton 31 July 1792; GD58/1/31 26 July 1794; GD58/1/31 18 September 1794; GD58/1/30 2 October 1794GD58/1/31 23 November 1794

^[5] Col. Fullarton of Fullarton, General View of the Agriculture of the county of Ayr, with observations on the means of its improvement. 1792 Published by the Ayrshire Archaeology and Natural History Society 2002

^[6] Mushet, David, On the Origins and Discovery of Iron: The Philosophical Magazine and Journal, Volume LX, July-December 1822 London pages 251-252

^[7] Woodcroft, Bennett, Alphabetical Index of Patentees of Inventions First published 1854 Patent Number 1891 19^th June 1792 "Refining Iron"