The work of Justus von Liebig and August Wilhelm von Hofmann laid the groundwork for modern industrial chemistry. Liebig is considered the "father of the fertilizer industry" for his discovery of nitrogen as an essential plant nutrient and went on to establish Liebig's Extract of Meat Company which produced the Oxo meat extract. Hofmann headed a school of practical chemistry in London, under the style of the Royal College of Chemistry, introduced modern conventions for molecular modeling and taught Perkin who discovered the first synthetic dye.