or GILBERD, WILLIAM, an eminent physician and experimental philosopher, was born at Colchester in 1540, and became famous in consequence of his discovery of several of the properties of the loadstone. He was a strenuous advocate for the inductive mode in philosophical matters, and was the first who proposed the theory of the great central magnet in the earth, afterwards applied by Halley to the explanation of the variation and dipping of the needle in the mariner's compass. Gilbert died in 1603.

Gilbert, Sir Humphrey, a celebrated English navigator of the sixteenth century, was born in 1539 in the county of Devon. By his mother's side, he was half-brother to Sir Walter Raleigh, who resembled him in many points of his character, and whose early life was chiefly guided and influenced by his example. He was educated first at Eton and afterwards at Oxford, and, embracing the military career, was sent to Ireland, where he contributed so powerfully to put down the rebellion raging there that in 1570 he was made a knight, and rewarded with the government of Munster. The idea of a north-west passage to Cathay and the Indies at this time occupied the thoughts of men, and in 1576 Gilbert published a treatise to prove the possibility of it. A perusal of this book induced Frobisher to set out on his first voyage to solve the mystery of the frozen north. In 1578 Gilbert was furnished with letters patent by the queen to take possession of the N.E. coast of America, and establish factories there. He was singularly unfortunate in his first setting out, having hardly set sail when a storm obliged him to return with the loss of one of his ships. In 1583, however, he again set out, and on the 5th August landed at St John's Bay, of which he took possession in the name of the English queen. On his way his fleet was assailed by a terrific storm, and the little vessel on board of which he was sailing went down, with all on board. Gilbert was one of those high-souled and adventurous men of whom the Elizabethan era was so prolific. There was almost no region of human thought or experience through which they did not pass. They were "soldiers, scholars, Christians, discoverers, and 'planters' of foreign lands, geographers, alchemists, miners, Platonic philosophers; many-sided and high-minded men, not without fantastic enthusiasm," an enthusiasm which led them on to enterprises that posterity, though reaping the benefit of them, has too often affected to pity as Quixotic, or sneer at as downright ridiculous. Tardy justice is now being done to these heroic souls, and there is even a prospect that Sir Humphrey Gilbert will at length find that recognition which has been denied him since his death. (Hakluyt's Collection, Biog. Univ.; North British Review, No. 45; Edin. Review, vol. lxxi., &c.)