This initialled, but undated, pencil drawing depicting a method of ventilating mineshafts by means of convection was with a collection drawings kept by William Symington's son. The collection included drawings of a diving bell, a novel clock and a blast furnace.

This simple coloured sketch illustrating a means of ventilating a mineshaft is self-explanatory. Initialled W.S., but not dated or otherwise inscribed, the drawing would have been made by the inventor himself. This was one of a series of drawings which William Symington had prepared at Falkirk in 1828 in order to document his various inventions. The other drawings in the series, which are more highly finished, are unsigned and may have been prepared by an illustrator under his direction.

William Symington's father John was employed as a mechanic at the mines at Leadhills, where William was born in 1764. James Stirling (1692-1770), the celebrated mathematician, had been appointed manager of the Scots Mines Company at Leadhills. Stirling took an interest in the ventilation of mineshafts and he submitted a paper to the Royal Society concerning a trompe, a water-powered air compressor, which was used to ventilate deep mine shafts at Leadhills. ^[1] William Symington would have observed Stirling's device which was employed in mines at Leadhills into the 1780's. ^[2] Symington may have considered his own system of ventilation would be advantageous when there was a dearth of surface water. No information has yet come to hand as to whether his method was put to use at Leadhills or Wanlockhead.

^[1] Philosophical Transactions of the Royal Society of London. 1744 43: 315–317

^[2] Harvey, W. S., Lead and Labour The story of the miners at Leadhills and Wanlockhead 2001 Chapter 3