August Wilhelm von Hofmann (April 8, 1818 - May 5, 1892) was a German chemist. He studied chemistry under Justus von Liebig at University of Giessen. In 1845, a school of practical chemistry was started in London, he was appointed its first director and many of the men who were trained there subsequently made their mark in chemical history. His work covered a wide range of organic chemistry. His first research was on coal tar and his investigation of the organic bases in naphtha established the nature of aniline. The Hofmann rearrangement and Hofmann elimination reaction bear his namesake. He isolated sorbic acid from rowanberries' oil in 1859, a chemical compound that is widely used as a food preservative. He was the first to introduce molecular models into public lectures. His color scheme is still in use by some scientists: carbon = black, hydrogen = white, nitrogen = blue, oxygen = red, chlorine = green, and sulfur = yellow. He invented the Hofmann voltameter an apparatus for electrolyzing water. He died in 1892 at the age of 74.