Directions for impregnating Water with Fixed Air

Joseph Priestley, 1772

Joseph Priestly (1733-1804) was an English Unitarian minister and chemist. it is to Priestly that we owe the discovery of oxygen, carbon dioxide, hydrogen and ten other types of gases. His mother died when he was 6 years old and he was raised by an aunt. Priestly was educated by a maverick minister and learned several languages, including Hebrew and Arabic. At the age of 22 he became a minister and began moving around Britain. In 1761 he moved to Lancashire to teach literature and languages at Warrington Academy, and in 1762 he married Mary Wilkinson of Wrexham, moving to Leeds and taking over Mill Hill. Because of the proximity of his home to a brewery, he became fascinated by the gases that emanated from fermenting beer vats, which later, through his experiments, were described as carbon dioxide.

Priestley found a way to combine carbon dioxide with water and discovered soda ash. In 1772 he published a paper in London entitled Directions for Impregnating Water with Fixed Air, in which he describes the process of dripping sulfuric acid on gypsum to produce carbon dioxide and forcing the gas to dissolve in a bowl of water by shaking it, thus creating soda water. The treatise is divided into three different sections: preparation, process, and observations and postscripts.

Priestley’s treatise, as far as Portugal is concerned, can be found in several libraries including the Portuguese National Library (BNP) in Lisbon and the library of the University of Coimbra.