"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 like sensible business men, and prepare for the future.
"We haven't a very big variety of vegetables, and I wish we could find some real good sweet potatoes and peas; and tomatoes would come in handy."
"Of course, variety, or the wish for different kinds, is largely a matter of desire. It is not a necessity."
"But does not the desire for different kinds grow out of the need of man to get the different substances which vegetables have?"
"To a certain extent, yes; but it is a singular thing that the world over there seems to be a natural instinct to combine two or three vegetables, and those vegetables, although they may be different in different countries, make chemical combinations, when eaten, which are almost identically similar. Thus, the Irishman mixes cabbages with his potatoes; the Englishman bacon with his beans, and the Italian rich cheese with macaroni."
One morning the boys were surprised to find a startling increase in their herd of yaks. When the Professor arose and went out for his regular morning stroll he noticed the unusual number, and was not slow in informing the boys.