John Frederic Daniell

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John Frederic Daniell
Daniell's hygrometer (wood engraving 1897)

John Frederic Daniell (born March 12, 1790 in London , † March 13, 1845 ibid) was a British physical chemist .

Daniell's cock from 1833
today's welding equipment

Live and act

He got his first job in a sugar factory . After attending a chemistry lecture by William Thomas Brande (1788–1866), he undertook his first own research. Around 1820 he succeeded in measuring the humidity using a dew point hygrometer he had invented . In 1823 Daniell dealt with atmospheric air currents . In 1827 he developed a process for obtaining luminous gas ( resin gas ) from rosin . In 1831 he was appointed Professor of Chemistry at King's College London .

Daniell's research into the development of constant current sources took place at the same time (late 1830s) when the first telegraph equipment was procured. The first telegrams were short and could only be sent over relatively short distances. Simple, weak batteries were enough to transmit the signal. With the increasing telegraph traffic and the further spread of the Morse code , higher currents and thus higher power sources became necessary. Daniell's copper-zinc element ( Daniell element ) (1836) and the nitric acid cell by William Grove were successful new developments. Daniell elements were mainly installed in British and American telegraph systems as they were the only available batteries with low self-discharge. In addition, the output voltage and current were uniform and the available current was higher than with standing batteries ( voltaic column ).

In 1839, Daniell experimented with a 70-cell battery to develop a new method for smelting metals . In the process, he created an arc that emitted UV radiation so strong that it immediately caused severe sunburn to everyone involved. During this experiment, the eyes of Daniell and others present were badly injured. Finally, Daniell showed that the ion of a metal, and not the oxide, carries the electrical charge when a corresponding metal salt solution is electrolyzed .

Another invention in 1833 was the “ Daniellsche Hahn ” - an oxyhydrogen gas blower operated with hydrogen and oxygen.

Daniell was a friend and admirer of Michael Faraday ; he dedicated his 1839 book "Introduction to the Study of Chemical Philosophy" to him.

Daniell died on March 13, 1845 in London while attending a meeting of the Council of the Royal Society.

Honors

In 1813 he became a member of the Royal Society , which awarded him the Copley Medal in 1837 and the Royal Medal in 1842 . From 1845 he was a corresponding member of the Prussian Academy of Sciences .

The following were named after him:

literature

  • Daniell, John Frederic. In: Kevin Desmond: Innovators in Battery Technology: Profiles of 95 Influential Electrochemists , McFarland, 2016, ISBN 978-0-7864-9933-5 , pp. 50-53
  • K. Jäger, F. Heilbronner (Ed.): Lexicon of Electrical Engineers , VDE Verlag, 2nd edition from 2010, Berlin / Offenbach, ISBN 978-3-8007-2903-6 , p. 94
  • Isaac Asimov: Biographical Encyclopedia of Natural Sciences and Technology , Herder, Freiburg / Basel / Vienna 1974, ISBN 3-451-16718-2 , p. 232
  • Arnold Thackray: Daniell, John Fredric . In: Charles Coulston Gillispie (Ed.): Dictionary of Scientific Biography . tape 3 : Pierre Cabanis - Heinrich von Dechen . Charles Scribner's Sons, New York 1971, p. 556-558 .

Web links

Commons : John Frederic Daniell  - Collection of pictures, videos and audio files
Wikisource: John Frederic Daniell  - Sources and full texts

Individual evidence

  1. ^ Newton, William: On Daniel's Patent Apparatus for Generating Gas from Rosin, as constructed by Mr. Martineau, for the London Institution, where it is in constant use . In: The London Journal of Arts and Sciences . tape 2 . Sherwood & Co., London 1828, p. 316-320 (English, full text in Google Book Search [accessed November 25, 2018]).
  2. ^ New oxyhydrogen blower from Daniell , in: Pharmaceutisches Centralblatt 1833, p. 60 ff
  3. ^ Entry on Daniell; John Frederic (1790-1845); Physicist in the Archives of the Royal Society , London
  4. ^ Members of the previous academies. John Frederic Daniell. Berlin-Brandenburg Academy of Sciences and Humanities , accessed on March 11, 2015 .
personal data
SURNAME Daniell, John Frederic
BRIEF DESCRIPTION British chemist
DATE OF BIRTH March 12, 1790
PLACE OF BIRTH London
DATE OF DEATH March 13, 1845
Place of death London