Justus Freiherr von Liebig (12 May 1803 – 18 April 1873) was a German scientist who made major contributions to agricultural and biological chemistry, and is considered one of the principal founders of organic chemistry. As a professor at the University of Giessen, he devised the modern laboratory-oriented teaching method, and for such innovations, he is regarded as one of the greatest chemistry teachers of all time. 

He has been described as the "father of the fertilizer industry" for his emphasis on nitrogen and trace minerals as essential plant nutrients, and his formulation of the law of the minimum, which described how plant growth relied on the scarcest nutrient resource, rather than the total amount of resources available.

He also developed a manufacturing process for beef extracts, and with his consent a company, called Liebig Extract of Meat Company, was founded to exploit the concept; it later introduced the Oxo brand beef bouillon cube. He popularized an earlier invention for condensing vapors, which came to be known as the Liebig condenser.

Although it was not widely adopted until after Liebig's death, when safety legislation finally prohibited the use of mercury in making mirrors, Liebig proposed a process for silvering that eventually became the basis of modern mirror-making. In 1835, he reported that aldehydes reduce silver salts to metallic silver.

After working with other scientists, Carl August von Steinheil approached Liebig in 1856 to see if he could develop a silvering technique capable of producing high-quality optical mirrors for use in reflecting telescopes. Liebig was able to develop blemish-free mirrors by adding copper to ammoniated silver nitrate and sugar. An attempt to commercialize the process and "drive out mercury mirror-making and its injurious influence on workers' health" was unsuccessful.

According to en.wikipedia