256 
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 
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. 
