the shamrock. St. Patrick taught the people that it
typifies the trinity with its three leaves. The plant has some very
peculiar qualities. It actually goes to sleep at night. It folds up its
leaves. It is so sensitive to light that it has at least four different
methods by which it can adjust itself with the greatest nicety to the
amount of light which it receives."

[Illustration: _Fig. 21. Fruit and Flower of Vanilla._]

"I think I have found vanilla; or it is something that smells like it,
but I did not know that the vanilla was a climber."

"You have found the wild vanilla, the flowers of which have, as you see,
disappeared and the bean is the product."

"I have often wondered why it is that we are able to smell or to
recognize different odors."

"Smell, like everything else in nature, is produced by vibrations. So is
sound, and light, and taste. Each odor has its particular rate of
vibration. They resemble very much the notes of a musical instrument,
and, as in music, odors can be harmonized, or they may be so mixed
together as to produce discord. Some perfumes, when used on the
handkerchief, and are about to fade away, have a sickly and disagreeable
odor. This is due to the admixture of the wrong or discordant tones.
Thus, heliotrope, vanilla, orange blossom and almond blend together;
citron, lemon, vervain and orange peel belong together, but they produce
a stronger impression on the sense of smell, and are of a higher octave;
and so with a still higher class, as patchouly, sandal-wood and
vitavert."

"But what is it in the flowers or essences which make them smell as they
do?"

"Carbon, hydrogen and oxygen. It is one of the most remarkable things in
nature that many of the odors in plants are formed by the combination of
only carbon and hydrogen, and the wonderful thing about it is, that
while turpentine is composed of 88 parts of carbon and 12 parts of
hydrogen, the odors of oils of lemon, orange and juniper and rosemary
have the exact proportions of those elements."

It was one of the duties of the colony to preserve the seeds of
different vegetables and grain, because the Professor intended to put
out for their use, as soon as spring came, a garden, which would avoid
the necessity of constantly putting them on the alert to hunt the
different foods. Sometimes it was necessary to go considerable distances
to get the various foods. As long as they were on the island it was the
part of prudence to act