Joseph Priestley

Joseph Priestley (March 13 1733–February 6 1804) was an English chemist, philosopher, dissenting clergyman, and educator. He is known for his investigations of carbon dioxide and the co-discovery of oxygen.

Leeds

On June 23 1762, Priestley married Mary Wilkinson of Wrexham, and by September 1767 the combination of his finances and her health caused him to relocate to Leeds. He there took charge of the Mill Hill congregation. In Leeds Priestley also published two political works, Essay on the First Principles of Government 1768 and The Present State of Liberty in Great Britain and her Colonies 1769, and also in 1769 Remarks on Dr Blackstone's Commentaries where he defended constitutional rights of dissenters against William Blackstone. Priestley's house was next to a brewery and Priestley began to experiment with the gas given off by fermenting beer. His first experiments involved demonstrating that the gas would extinguish lighted wood chips. He then noticed that the gas appeared to be heavier than normal air as it remained in the vats and did not mix with the air in the room. The gas, which Priestley called "fixed air" and had already been discovered and named "mephitic air" by Joseph Black, was carbon dioxide. Priestley discovered a method of impregnating water with the carbon dioxide by placing a bowl of water above a vat of fermenting beer. The carbon dioxide soon became dissolved in the water and Priestley found that the impregnated water developed a pleasant sweet acidic taste. He began to offer the treated water to friends as a refreshing drink. In 1772 Priestley published a paper entitled Impregnating Water with Fixed Air in which he described a process of dripping sulphuric acid (or oil of vitriol as Priestley knew it) onto chalk in order to produce carbon dioxide and forcing the gas to dissolve by agitating a bowl of water in contact with the gas. In December of 1772 Priestley was hired by Lord Shelburne, as his personal librarian, and stayed in that post until 1780.

Related Topics:
June 23 - 1762 - September - 1767 - 1768 - 1769 - Brewery - Beer - Joseph Black - Carbon dioxide - 1772 - Sulphuric acid - Oil of vitriol - December - Lord Shelburne - 1780

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In 1772 Priestley wrote Observations on Civil Liberty and the Nature and Justice of the War with America. Whilst tutoring his benefactor's sons at Bowood House near Calne in 1774 he discovered oxygen, unaware of Carl Wilhelm Scheele's prior discovery sometime before 1773. Priestley discovery was published in 1775 in Experiments and Observations on Different Kinds of Air and in 1777 Scheele's discovery was published in his book Chemical Treatise on Air and Fire. Both Priestley and Scheele were unaware that oxygen was a chemical element; Priestley named the gas (which he had generated by heating red mercuric oxide with a "burning lens") "de-phlogisticated air", in accordance with the phlogiston theory which held at the time. In his experiments he managed to identify eight distinct gases, disproving the commonly held view that there was just one "air".

Related Topics:
1772 - Bowood House - Calne - 1774 - Oxygen - Carl Wilhelm Scheele - 1775 - 1777 - Chemical element - Phlogiston theory

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There is a statue of Priestley in Leeds City Square.

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