Letter from Stephen Hales, Teddington, Near Hampton Court dated 16 August 1746 He discusses the use of ventilators in the preservation of corn and in the prevention of gaol distemper [typhus] on board convict ships; Hales informs about the ventilators he has recently installed in Newgate Prison; He includes copies of essays he has published on ventilators and asks him [Duhamel] to let him know about experiments he has made with ventilators as he [Hales] is intending to produce an appendix to his book, giving accounts of experiments and making suggestions for improvements. He also sends a proposal for bringing passable stones out of the bladder. He explains in detail the defects of centrifugal fans as forms of ventilation; and expresses the hope that his correspondent will have an opportunity of sending, by means of French prisoners coming to Dover from Calais, the treatise he was printing.

The letter was sent via French prisoners in Dover Castle where his nephew, Thomas Hales, was deputy governor.

There is an accompanying typed translation in French.