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

Imagine the oxygen removed (which in the quartz is combined with silicious substance) and you have so-called silicon. This substance is included by modern chemistry among the “elements,” oxygen, nitrogen, hydrogen, sulphur, etc. Silicon therefore, which is here combined with oxygen, is a “chemical element.” (Steiner 2007:12)

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