532 Geological Society : Anniversary Address. 



Theory of Suspension Bridges (vol. 116, 1826, Parti., p. 202); 

 also a Table for facilitating ^he Computations relative to Suspension 

 Bridges (vol. 121, 1831, p. 341); a third paper, entitled Observa- 

 tions on Steam Engines (vol. 117, 1827, p. 25); and a fourth on the 

 Efficacy of Steam Engines in Cornwall, with Investigations of the 

 Methods best adapted for imparting great Angular Velocity (vol. 120, 

 1830, Part I., p. 121); likewise a paper on the nature of Negative 

 and Imaginary Quantities (vol. 121, 1831, p. 91). He also printed 

 three Addresses as President of the Royal Society, 1828, 1829, 

 1830*. 



In 1804 he was returned to parliament for the borough of Hel- 

 ston; and in 1806 for Bodmin, which place he represented till 1832. 

 During that time he was continually called on by the House of Com- 

 mons to serve on committees of inquiry touching scientific and finan- 

 cial questions, on which latter subject he published a letter, entitled 

 "A plain Statement of the Bullion Question." He was Chairman of 

 the Committee for rebuilding London Bridge, which he^caused to 

 be widened ten feet. The rectification of the national standards of 

 linear dimensions and capacities, was undertaken upon his motion 

 for an address to the Crown. 



In his native county also, his authority was continually appealed 

 to on scientific questions, and calculations of practical importance 

 in the machinery of mines and steam-engines ; and he was ever 

 ready on all occasions to devote his time and talents to the service 

 of his friends and of the public. In 1792, on the occurrence of a 

 riot in Cornwall, whilst he was a young man, holding the office of 

 sheriff, there being no soldiers in the county, he performed, for the 

 last time that such an event has occurred in England, the military 

 duty of calling out the posse-comitatus. 



Few persons excelled Mr. Gilbert in bringing the results of much 

 contemplative study to bear on the business of life ; his strong 

 point lay in the application of high mathematical knowledge to 

 practical purposes, and in calculating the amount of effective power 

 to be derived from the use of mechanical forces, judiciously com- 

 bined. For the exercise of this talent his beloved native county 

 offered unusual opportunities ; it also afforded him abundant mate- 

 rials for gratifying his taste for antiquarian researches ; and the fruits 

 of his labours as a biographer and local historian were presented 

 to the public in 1838, in four 8vo vols. ; this work is entitled 

 The Parochial History of Cornwall, founded on the manuscript 

 histories of Mr. Hals and Mr. Tonkin, with additions and various 



* Mr. Gilbert was also the author of the following papers in the Quar- 

 terly Journal of Science and the Arts : Observations on the properties of 

 the Catenarian Curve with reference to Bridges by Suspension, vol. x. 

 p. 230; On the Ventilation of Rooms, and the Ascent of Heated Gases 

 through Flues, vol.xiii. p. 113; Investigation of the Methods used for ap- 

 proximating to the Roots of Affected Equations, vol. xiv. p. 353 ; Re- 

 searches on the Vibrations of Heavy Bodies in Cycloidal and Circular 

 Arches, vol. xv. p. 90; On the General Nature and Advantages of Wheels 

 and Springs for Carriages, the Draft of Cattle, and the Form of Roads, 

 vol. xviii. p.. 95; On the Vibration of Heavy Bodies, vol. xx. p. 69. 



