From the abundance of wood used in the houses, the island must in those days have been well supplied with timber. The olive-tree grew freely, and barley was the commonest of the cereals. Probably too the climate was different. The vine does not seem to have been there; still less was it the only plant cultivated, as now, at Santorini. The population were husbandmen, understanding how to grind barley in mills and make it into bread; how to press oil from olives, to bring up cattle, and to weave stuffs. Yet the great abundance of utensils of lava, obsidian, and flint, without any metals, shews that theirs was the age of stone, when the use of metals was unknown. The blocks of stones at the angles of the house at Therasia and the column standing near, indicate considerable skill in the workmen, when the kind of tools they used is taken into consideration; whilst the vases of pottery-ware are remarkable for their elegance of form. It only remains to consider how many years ago it is since this great eruption took place. The data are vague, but geologists have tried to make some approximation. It is well known that after any violent catastrophe the subterranean forces seem to be exhausted; the periods of repose in a volcano are proportional to the previous energy. About one hundred and ninety-six years before Christ there is the record of an eruption, which raised in the centre of the bay a small islet called Palæa Kameni. After the Christian era, frequent slight emissions only served to increase the size of the island, and during the middle ages there was a period of calm. In the fifteenth century the excitement again burst forth, raising reefs both inside and outside the bay. The second duration of rest was about ten centuries; so that to the first, according to its intensity, there may be calculated at least twice that time; thus the formation of the bay was perhaps two thousand years B.C.