Alexander John Gaspard Marcet FRS (1 August 1770 – 19 October 1822), was a Genevan-born physician who became a British citizen in 1800.

[1][2][3] His wife Jane Marcet was a prolific author, whose series of books entitled 'Conversations' treated topics such as chemistry, botany, religion and economics.

[4] In 1805, Marcet contributed an essay, A Chemical Account of the Brighton Chalybeate, to a new edition of the Treatise on Mineral Waters of his colleague, William Saunders.

He describes a variety of experiments of the rudimentary chemistry of that period made with the water of a chalybeate spring called the Wick, and shows that, unlike the Tonbridge spa, it might be drunk warm without any precipitation of iron.

He was probably the first to remark that the pain of a renal calculus is often due to its passage down a ureter, and that it may grow in the kidney without the patient suffering acutely at all.