Page:Popular Science Monthly Volume 13.djvu/657

Rh were principally engaged. In less than two minutes every sign of hostility had ceased except in the case of one small group and two single combatants in the opposite end; but a small pellet of perfumed paper, dropped in their neighborhood, put an end to the battle here. Previous to this, occasional stragglers had passed along the connecting glass tube into the smaller box. Most of them seemed to be of one faction, only one of the opposition having entered, upon whom six or eight ants were expending their wrath. This was the only remaining centre of strife, when Mr. McCook replaced ants and earth upon their native territory. The battle was continuing there, between greatly-diminished numbers of course, after the removal of the large battalions into the box, but the application of a feather dipped in cologne to the neighborhood of the warriors caused the instant cessation of controversy. The next day there were no ants found upon the surface, but digging two inches under ground, close by the fence, he observed a few. The battle was evidently over. There had been in the mean time a great change of temperature, from 96° to 47° Fahr., and this may have had some effect in sending the ants underground.

How the Lake-Dwellers lived.—A recently-published work on "The Lake-Dwellings of Switzerland" throws much needed light on the mode of life followed by the inhabitants of those curious constructions. That they must have been expert fishermen is shown by the large number of fish-skeletons, especially the skull of very large pike, found buried among the piles. So, too, the bones, which lie about in the lake dwellings in astonishing numbers, of stags, roes, wild-boars, beavers, squirrels, etc., are an evidence of the abundance of game, and of the ability of the settlers to capture even the higher description of wild animals. But the lake-dwellers did not depend on the chance products of hunting and fishing. They had already domesticated many of the animals, which to-day are the companions of man—as cows, sheep, goats, pigs. A great variety of seeds and plants were also cultivated by them for their own use and that of their domesticated animals. They cultivated flax of excellent quality; and their textile and other manufactures show considerable proficiency and skill. Tools and utensils of flint, of bronze, and of iron, have been found in the sites of these lake dwellings, and the question arises whether the inhabitants were one people through the three successive ages of Stone, Bronze, and Iron, or whether each age was heralded by a new invasion. The evidence goes to prove the former hypothesis, of one race successively advancing from one stage of civilization to another.

Rapid Decay of Timber.—Till recently chestnut-timber has been always employed for beams in constructing houses in Rome, but, in most of the houses built since the occupation of the city by the Italian Government, pine joists have been used. After a few years the roofs and floors in which the pine had been employed were found to be falling, the joists having rotted at the point of junction with the walls, while the intermediate portions remained sound. The cause of this decay was discovered by accident on taking down the scaffold which had been erected for the use of the workmen engaged in building the hall of the Ministry of Finance. A correspondent of Prof. Tyndall's, writing from Rome, states that around one of the scaffold-poles, which was imbedded some four feet in the ground, had accumulated a heap about six feet high of pozzuolana mortar—that is, mortar made of lime and the peculiar argillaceous sand, of volcanic origin, known as pozzuolana. The underground portion and that above the mortar-heap were perfectly sound; that covered by the mortar was utterly rotten. Hence it was clear that the mortar was to blame. In what respect, then, does Roman mortar differ from that used in Venice, for instance, where pine-timber has stood in mortar for centuries without impairment? The sole difference was in the use of pozzuolana, which therefore seems to have some special chemical affinity for pine, while, as regards chestnut, it is neutral. It is stated that, in consequence of this peculiar action of the Roman mortar on the pine-timbers of the numerous buildings erected on the Esquiline Hill since 1870, many of the roofs and floors have had to be renewed.