 In 1846, he became an assistant in the Inland Revenue Laboratory at Somerset House, established to carry out the provisions of the Tobacco Act 1842; and was successively deputy principal from 1867 to 1874, and principal from 1874 till his resignation in 1894.The work of the laboratory was extended to alcoholic products; and when the Food and Drugs Act 1872 was amended in 1875, Bell was made chemical referee when disputed analyses of food were brought to court.Bell elaborated methods for analysing chemically foods within the operation of the Act.