GILBERT, SIR JOSEPH HENRY English chemist, was born at Hull on Aug. I, 1817. He studied chemistry first at Glasgow ; then at University College, London; and finally at Giessen under Liebig. He was for 58 years director of the chemical laboratory at the experimental station established by Sir J. B. Lawes at Rothamsted, near St. Albans, for the systematic study of agriculture. He died on Dec. 23, 1901. The work which he carried out in collaboration with Lawes involved the applica tion of many branches of science, such as chemistry, meteorology, botany, animal and vegetable physiology and geology; its influence in improving the methods of practical agriculture extended all over the civilized world. His name is perhaps best associated with the development of the "nitrogen" theory of fertilizers as opposed to the "mineral" theory of Liebig (q.v.). Gilbert was elected a fellow of the Royal Society in 1860, and in 1867 was awarded a Royal medal jointly with Lawes. In 1882 he was president of the London Chemical Society, and for six years from 1884 he filled the Sibthorpian chair of rural economy at Oxford. He was knighted in