Carbono, nitrogênio, silício e cálcio em Steiner (2007)

This is the kind of vision we must unfold when we look out over he surface of the Earth, covered as it is with plants and having beneath it the limestone and the silica — the calcium and silicon. We cannot look inside the human being; we must evolve the same knowledge by looking out over the Earth. There we behold the oxygen-nature caught up by the nitrogen and carried down into the carbon-nature. (The carbon itself, however, seeks support in the principles of calcium and silicon. We might also say, the process only passes through the carbon). That which is living in our environment — kindled to life in the oxygen — must be carried into the depths of the Earth, there to find support in the silica, working formatively in the calcium or limestone.(Steiner 2007:27)

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