In the Year 1740, I wrote to Dr. Martin Physician to Lord Cathcart, General of the Forces which lay imbarked at Spithead, for an Expedition in Americ… - Stephen Hales

A Translation of which ingenious Treatise, was communicated to me by Dr. Mortimer; in which he says, "In Hospitals and Barracks for the Sick, this Machine is placed in the , from whence two or three Pipes go down, some Inches thro' the Ceiling, into each Room where the Sick lie; and thus draw out all the unwholesome Air and Stench, which does more harm than any Physick can repair. And at the same time, has this accidental Benefit, That those who begin to mend, may give themselves a proper Exercise, in working the Machine: Only they ought to take care to keep all the Garret-Windows open, while the Machine is a going. In Men of War and Hospital-Ships, this Machine is placed on the upper Deck, directly over the great other Hatch: And then the Pipe, which goes down between the Decks, draws out the unwholesome Air; which is instantly supplied by fresh.

We have seen in the Course of these Experiments, the Quantity of Tar that there is in Tar-Water; and the great Difference of that Quantity, made with different kinds of Tar, and different Degrees of Stirring. Now, since, notwithstanding these Quantities of Tar, and the additional more subtile volatile Oil, which flies off in Evaporation, it has yet undoubtedly proved an efficacious Remedy in many Cases and Instances; it may hence be reasonably concluded, that the Medicinal Virtue of the Water does not reside solely in the Acid, but partly also in the unctuous oily Parts, which are so temper'd by the Acid, as in some Cases to prevent their heating too much.

It is in like manner also that they destroy and burn up the Lungs. Hence also it is, that by frequently contracting and shrivelling, and then soon after relaxing, they weaken and wear out the Substance and Coats of the Stomach, on which they more immediately prey, every time they are drank.