To show how damp or stale air might be drawn out from a coal-pit or any sort of mine, well or subterraneous cavern by an engine designed by Dr Desaguliers Also how fresh air might be conveyed into a particular part of a mine through several hollows which are full of stale air That a working model of the machine had been made to the scale of an inch to a foot - the model consists of a triple crank working three pumps which suck and force air by means of three regulators Outlines four experiments with comments Read to the Royal Society on 18 May 1727 1727