John Frederic Daniell FRS (12 March 1790 – 13 March 1845) was an English chemist and physicist.

Daniell was born in London. In 1831 he became the first professor of chemistry at the newly founded King's College London; and in 1835 he was appointed to the equivalent post at the East India Company's Military Seminary at Addiscombe, Surrey.^[1] His name is best known for his invention of the Daniell cell,^[2] an element of an electric battery much better than voltaic cells. He also invented the dew-point hygrometer known by his name,^[3] and a register pyrometer;^[4] and in 1830 he erected in the hall of the Royal Society a water-barometer, with which he carried out a large number of observations.^[5] A process devised by him for the manufacture of illuminating gas from turpentine and resin was in use in New York City for a time.^{[citation needed]}

In 1842 he was awarded an honorary Doctorate of Civil Law by the University of Oxford.^[1]

Daniell's publications included Meteorological Essays (1823), an Essay on Artificial Climate considered in its Applications to Horticulture (1824), which showed the necessity of a humid atmosphere in hothouses devoted to tropical plants, and an Introduction to the Study of Chemical Philosophy (1839).^{[citation needed]}

In 1840 he was invited to deliver the Royal Institution Christmas Lecture on The First Principles of Franklinic Electricity.^{[citation needed]}

Daniell died suddenly of apoplexy in London in March 1845, while attending a meeting of the council of the Royal Society, of which he had become a fellow in 1813 and Foreign Secretary in 1839.^{[citation needed]}

The lunar crater Daniell is named after him.^{[citation needed]}

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