"In the study of paleontology an effort has been made to classify the different periods of man's life on the planet, so that we have the stone age, which is the earliest, the bronze age, and the age of iron."
"How far back in the history of the world has evidence been found of the existence of man?"
"In the chalk cliffs of England, and also in like formations in Germany, skulls have been found which indicate an existence back to a period fully 500,000 years ago."
"What reason is there to assume that if they were found in those chalk deposits, that they must have been that far back?"
"Because it was fully that long ago in the period of the world formation when the chalk beds were made, and this seems to be conclusive evidence of great antiquity."
"Is it not singular that more evidence of that condition is not found than the recovery of a few bones?"
"Not when it is considered that the earth is constantly undergoing change, first in one place and then in another. Have you ever heard of the great continent, which was supposed to be lost in mid-Atlantic, called Atlantis? Plato refers to it, and attributes the first knowledge of it as coming from Solon, who visited Egypt and there learned from the wise men that a great country, to the west of the Pillars of Hercules, which Gibraltar was called in ancient times, had disappeared thousands of years before; and they further informed the great Grecian lawgiver that the earth had been peopled and repeopled many times before in ages past."
"Why was it necessary to repeople the earth? Were they all destroyed?"
"They pointed out that at certain stages of the world's history great floods came and destroyed all the people inhabiting the low places, and at other times the terrific volcanic eruptions destroyed those who lived in the hills, and at other times entire continents, like Atlantis, disappeared, so that the earth had to be repeopled and the arts and sciences learned over anew."
It is wonderful to relate how the life on the island affected the health of all. They lived outdoors and had plenty of sunshine and vigorous exercise. In the laboratory, the Professor made it a constant habit to do all his work in the sunlight, to which he exposed himself at all times. The boys often spoke of this, and one day, while talking on the subject, he remarked: