MALLET

mallet, robert (1810-1881), irish engineer, physicist and geologist, was born in dublin, on the 3rd of june 1810. he was educated at trinity college in that city, and graduated b.a. in 1830. trained as an engineer, he was elected m.inst.c.e. in 1842; he built in 1848-1849 the fastnet rock lighthouse, south-west of cape clear, and was engaged in other important works. devoting much attention to pure science, he became especially distinguished for his researches on earthquakes, and from 1852-1858 he was engaged (with his son john william mallet) in the preparation of his great work, _the earthquake catalogue of the british association_ (1858). in 1862 he published two volumes, dealing with the _great neapolitan earthquake of 1857_ and _the first principles of observational seismology_. he then brought forward evidence to show that the depth below the earth's surface, whence came the impulse of the neapolitan earthquake, was about 8 or 9 geographical miles. one of his most important essays was that communicated to the royal society (_phil. trans._ clxiii. 147; 1874), entitled _volcanic energy: an attempt to develop its true origin and cosmical relations_. he sought to show that volcanic heat may be attributed to the effects of crushing, contortion and other disturbances in the crust of the earth; the disturbances leading to the formation of lines of fracture, more or less vertical, down which water would find its way, and if the temperature generated be sufficient volcanic eruptions of steam or lava would follow. he was elected f.r.s. in 1854, and he was awarded the wollaston medal by the geological society of london in 1877. he died at clapham, london, on the 5th of november 1881.