TYNDALL, JOHN, physicist, was b. Aug. 21, 1820, at Leighlin Bridge, county Car low. He had few educational advantages. On returning from the continent, where lie received part of his education, he found employment in one of the subordinate grades of the ordnance survey. He was afterward appointed teacher of natural philosophy at Queenwood college, Stockbridge, and there commenced those original investigations which have distinguished him among the explorers of science.
In Jan., 1853, Tyndall communicated his first paper to the royal society, On Molecu lar influences—Transmission of heat through Organic Structures. It exhibits much of that skill in experimenting and fertility of resource which characterize his subsequent researches, and illustrates certain important questions in natural philosophy.
Year by year from the date above mentioned, Tyndall has extended our knowledge of science. His field of research is wide and varied, as exemplified by the subjects of his papers published in the Philosophical nansactions—On the Vibrations and Tones pro duced by tire Contact of Bodies having Different Temperatures (1854); On the Physical Phe nomena of Glaciers (1857); On some Physical Properties of Ice (1858-59); On gransmissioa of Heat through Gaseous Bodies (1859); a series on Radiation, six papers (1861-65); 0• CalOrescence (1865); On the Invisible Radiation of the Electric Light (1565). Durn.:,!, year 1867, he lectured on Sounding arid Sensitive rhymes.
In 1855, and again in 1861, Tyndall was appointed to deliver the Bakerian lecture to the royal society: the subjects were: On the _Nature of the Force by which Bodies are se pelted from the Poles of a Magnet,. and On the Absorption and Radiation of Real by Gases and Vapors, and on the Physical Connection of Radiation, Absorgion, and Conduction, the latter being one of the series on Radiation above mentioned. The publication of this series of papers marks a period in the history of scientific research, for the facts therein set forth, and the conchisions drawn from them, demonstrate the relation of aqueous vapor to radiant heat, and elucidate certain meteorological phenomena which connect themselves with some of the profoundest and most interest:lig questions of cos mieal science.
In 1864 the council of the royal society awarded to Tyndall their Rumford medal, In recognition of his scientific researches, particularly as bearing on light and heat. As a lecturer on scientific subjects, Tyndall enjoys a high reputation. His lectures at the royal institution and the school of mines have been marked by fullness of knowl edge and clearness of illustration. Tyndall has experimented and written on the sub ject of germs, and on' the acoustic transparency or cloudiness of the atmosphere.
In 1852, Tyndall was elected a fellow of the royal society. In 1853 he was appointed professor of natural philosophy in the royal institution, where, as successor to Davy and Faraday, he sustains the reputation of the place for original scientific research. His lectures at the school of mines have been attended by.erowds of workingmen. He is LL.D. of Cambridge, and is a member of a number of the scientific societies of the con tinent. He was chosen president of the British association in 1874. Besides his papers for the royal society, Tyndall has written articles in the Philosophical Magazine and The Fortnightly'Revimo. His separate works comprise: The Glaciers of the Alps, being a Nar rative of Excursions and Events (1860); Mountaineering in 1861 (1862); heat considered as a Mode of Motion (2d ed., 1863); Radiation, being the Bede lecture, delivered at Cam bridge in 1865; Lectures on Sound (1867); a memoir of prof. Faraday (1868); Fragments of Science, and flours of Evercise in the Alps (1871); Six Lectures on Il;qht (1873); and Ad dress delivered before the British Association in 1874, with Additions 71874). In 1876, Tyn dall was married to a daughter of lord Claud Hamilton.