provides the basis of the innumerable organic substances in nature, and
serves as the 'building stones' of the body-substances of living
organisms. Among these, the carbohydrates produced by the plants show
clearly the double function of carbon in the way it alternates between
the states of starch and sugar.

When the plant absorbs through its leaves carbonic acid from the air
and condenses it into the multiple grains of starch with their peculiar
structure characteristic for each plant species, we have a biological
event which corresponds to the formation of snow in the meteorological
realm. Here we see carbon at work in a manner functionally akin to that
of phosphorus. Sugar, on the other hand, has its place in the saps of
the plants which rise through the stems and carry up with them the
mineral substances of the earth. Here we find carbon acting in a way
akin to the function of sulphur.

This twofold nature of carbon makes itself noticeable down to the very
mineral sphere of the earth. There we find it in the fact that carbon
occurs both in the form of the diamond, the hardest of all mineral
substances, and also in the form of the softest, graphite. Here also,
in the diamond's brilliant transparency, and in the dense blackness of
graphite, carbon reveals its twofold relation to light.

In Fig. 6 an attempt has been made to represent diagrammatically the
function of Carbon in a way corresponding to the previous
representation of the functions of Sulphur and Phosphorus.

*

By adding carbon to our observations on the polarity of sulphur and