Page:Popular Science Monthly Volume 13.djvu/787

Rh A New Theory of the Flow of Sap.—In a new theory of the ascent of sap in trees, proposed by Joseph Böhm, the elasticity of the plant-cells plays an important part. When the superficial cells have lost through evaporation a portion of their water, they partly collapse under the action of the air-pressure; but, like elastic bladders, they tend to resume their original form. This they can do only by drawing in either air or water from without. But since moist membranes are but little permeable by air, the cells draw from the cells farther toward the centre a portion of their liquid contents; these in turn draw on the cells farther down, and so on down to the roots. The author illustrates his theory by an apparatus which represents a chain of cells. A funnel closed by a bladder represents the evaporating leaf; to it are connected below several glass tubes about two inches wide, closed at one end with a bladder, and joined together in series by means of thick caoutchouc tubes. As evaporation goes on, the membrane which closes the funnel-mouth is bent inward, and, when it has reached a certain tension, water is sucked into the funnel out of the cell next below, which covers its loss in the same way. Manometers connected with certain cells of the apparatus indicate the amount of suction at different heights.



is made in the newspapers that fish and fowl are dying by millions in different parts of the country, poisoned, it is supposed, by Paris-green. In the valley of the Connecticut Paris-green is freely used to destroy the potato-beetle, and the recent heavy rains have washed it into the rivers, together with untold millions of poisoned beetles. It may be doubtful whether the Paris-green suspended in the stream could destroy many fish, but there is little doubt that eating the poisoned beetles would prove fatal both to fish and fowl. "There is no reason advanced," says the Hartford Courant, "to explain the wide-spread destruction of fish more plausible than this, and it is a singular fact that sportsmen on land have complained of a fatality among birds, the same as fishermen do of the fatal effects upon fish. Quail have been found dead in various parts of the State, and there is no doubt that the death of the birds is due to agricultural poisoning."

to a Pittsburg newspaper, Messrs. Gemill and Wampler, of McKeesport, at 10 of July 11th, while observing the planet Jupiter with a five-inch telescope, noticed on the eastern limb a dark round spot, just above the northern belt of the planet. Soon it moved rapidly westward, just touching the belt and passing off the face of the planet at 1.24 of the 12th. It had the appearance of a perfect sphere much larger than any of Jupiter's satellites, sharply defined, and intensely black. It could not have been a spot on the disk of Jupiter, for it passed over the face of the planet in three hours and nineteen minutes, while a spot would have taken five hours. Neither was it a satellite, or the shadow of one, for all the four Jovian satellites were in full view the whole time.

of Cologne, has discovered a new crater on the moon's surface, situated in the Mare Vaporum, a little to the northwest of the crater Hyginus. The new crater is nearly as large as Hyginus, and is a conspicuous object. Klein, though he had previously again and again observed the same region, had never seen this crater; neither had it been noticed by other selenographers. The inference would appear to be that volcanic action is still going on in the moon.

a session of an educational committee, the Bishop of Gloucester in the chair, one of the members lamented the very imperfect education given to girls under the present system. "The fact cannot be denied, I fear," said the chairman, "but there is one consolation—the boys will never find it out."

meeting, of persons of both sexes, was recently held in Indianapolis, Indiana, for the purpose of forming a cremation society. A committee was appointed to draft a constitution and by-laws.

is a pleasing picture that Sir David Wedderburn draws of the social usages of the people of Japan—"a country where men never lose their temper, where women and children are always treated with gentleness, where common laborers bow and beg pardon of each other if they happen to jostle accidentally, where popular sports do not inflict suffering on the lower animals, and where cleanliness takes such a high rank among social virtues as to be carried almost to a ludicrous excess;" and their courtesy is "singularly free from servile or mercenary considerations."

twenty-five years ago the British Association for the Advancement of Science met in a certain cathedral town, and in the Geological Section a rather warm debate arose about the truth of the Mosaic account 