"November the sixth following, viz. in the Year 1741 Martin Triewald, Captain of Mechanicks and Military Architect to the King of Sweden, and Fellow of the Royal Society at London, in a Letter to M.D. and Secretary of the Royal Society, says, that "this Spring he had invented a Machine, for the Use of his Majesty's Men of War, which went to block up Petersburgh, in order to draw out the bad Air from under their Decks, the least of which does exhaust 36172 cubick Feet of Air in an Hour,"..."