Hidrogênio, nitrogênio, oxigênio e enxofre em Steiner (2007)

You know that in the growth of plants, all the four elements of which I have been speaking are involved. Hydrogen also is there, in addition to sulphur. I have told you of the significance of hydrogen. Now there is a mutual and qualitative relationship between the limestone and the hydrogen, similar to that between oxygen and nitrogen in the air. (Steiner 2007:47)

STEINER, Rudolf. 2007. The Agriculture Course. (Trans.: George Adams) Shrewsbury: Wilding & Son Ltd.