Page:Biographies of Scientific Men.djvu/133

 did not produce more than fields in which this ingredient was deficient. Although Liebig's theory of plant nutrition was essentially a mineral theory, yet he understood that organic matter (humus) decomposes in a soil, giving rise to carbonic acid and ammonia; and these gaseous bodies are also valuable plant foods. Liebig fully established the following important laws of husbandry:—

These laws of Liebig form the basis of modern scientific agriculture.

Liebig was the first to treat bones with "Schwefelsäure" or sulphuric acid in order to make the calcium phosphates soluble (superphosphate); and the late Sir John B. Lawes was the first to commence the manufacture of superphosphate on a large scale, both from bones and mineral phosphates.

From these early beginnings an enormous industry