A description of ventilators [electronic resource] : whereby great quantities of fresh air may with ease be conveyed into mines, goals, hospitals, Work-Houses and Ships, In Exchange for their Noxious Air. An Account also of their Great Usefulness in many other Respects: As in Preserving all Sorts of Grain Dry, Sweet, and free from being Destroyed by Weevels, both in Grainaries and Ships: And in Preserving many other Sorts of Goods. As also in drying Corn, Malt, Hops, Gun-Powder, &c. and for many other useful Purposes. Which was read before the Royal Society in May 1741. By Stephen Hales D. D. F. R. S. Rector of Faringdon, Hampshire; And Minister of Teddington, Middlesex.