An Account of a Useful Discovery to Distill Double the Usual Quantity of Sea-Water, by Blowing Showers of Air Up Through the Distilling Liquor: And an Account of the Great Benefit of Ventilators in Many Instances, in Preserving the Health and Lives of People, in Slave and Other Transport Ships ... Also an Account of the Good Effect of Blowing Showers of Air Up Through Milk, Thereby to Cure the Ill Taste Which Is Occasioned by Some Kinds of Food of Cows.

A scientific publication written in the mid-18th century. The book discusses innovative methods for distilling seawater to produce fresh water and emphasizes the importance of ventilation in ship health, particularly in minimizing disease during long voyages. Hales elaborates on both his distillation methods and the implementation of ventilators to improve air quality aboard ships, which he argues is crucial for the health of crews and transported populations. In the book, Hales details his new method of water distillation, which significantly increases efficiency and output by introducing air into the boiling seawater. He provides experimental evidence demonstrating that this approach can produce nearly double the water compared to traditional methods. Furthermore, he examines the effectiveness of ventilators in ships, highlighting numerous cases where they resulted in better health outcomes for passengers and crew by reducing exposure to foul and stagnant air. Hales concludes that these innovations could greatly benefit navigation and maritime health, reducing the mortality rates often associated with voyages in cramped and poorly ventilated conditions, particularly on transport and slave ships.