(1767-1839), MP, scientist, antiquary

Davies Gilbert (formerly Giddy) was born on the 6th March 1767 at St Erth, Cornwall. He was educated at Penzance grammar school, from about 1775 to 1779, at home by his father, and at Benjamin Donne's mathematical academy in Bristol before matriculating at Pembroke College, Oxford, as a gentleman commoner on 12 April 1785.

After Oxford, Giddy began a decade of county service, he served as high sheriff of Cornwall in 1792–3 and was appointed deputy lieutenant in 1795. Serving as member of parliament first for Helston (1804–6) and then for Bodmin (1806–32) Giddy refused office under successive ministries but chaired numerous parliamentary committees, drafting and shepherding many items of legislation.

Gilbert married, on 18 April 1808 at Northiam, Sussex, Mary Ann (1776–1845), daughter of Thomas Gilbert of Eastbourne and heir to substantial estates in Sussex. These estates passed to Giddy on the death of his wife's uncle in 1814 with a condition that the name of Gilbert be perpetuated. By royal sign manual Davies Giddy became Davies Gilbert on 10 December 1817 and the family names of his children were changed.

Gilbert was a significant figure in the scientific community of his day, though he published little of major importance. In the Quarterly Journal of Science (1821) and the Philosophical Transactions (1826, 1831) he published his mathematical investigations into the catenarian curve and suspension bridge design. Thomas Telford's plans for the Menai suspension bridge, and the strength of the bridge itself, were improved thanks to Gilbert's theoretical calculations. His methods remained in use for a century. Gilbert also published on other mathematical topics and on the efficiency of steam engines, producing some thirteen scientific papers in all.

He was elected to the Royal Society on November 17, 1791 and served as its President of the Royal Society from 1827 to 1830. He was also a supporter of the Royal Institution, recommending Humphry Davy to its employ and maintaining close contact with Davy's work there. In 1814 he was a founder and first president of the Geological Society of Cornwall. In his declining years Gilbert was involved in the affairs of the newly founded British Association for the Advancement of Science. Cambridge the university gave him an honorary doctorate of laws in 1833.

He died at Eastbourne on 24 December 1839. He was survived by his wife, three daughters, Catherine (b. 1813), Anne (b. 1817), and Hester Elizabeth (b. 1818), and a son, John Davies Gilbert FRS (1811–1854).