Page:Popular Science Monthly Volume 7.djvu/781

Rh but a minute quantity of animal acids, of composition analogous to those secreted by the flea or the bed-bug. In the insect last named there are special organs for the secretion of these acids, but no such organs have been found in the potato-bug. The conclusion reached by the authors is, that the potato-bug is not poisonous, and that the cases on record of poisoning supposed to be caused by the bug are in fact traceable to Paris-green.

In the discussion which followed the reading of this paper. Prof Riley said that his own investigations had satisfied him of the poisonous properties of the doryphora. "Experiments on frogs," said he, "are not conclusive. Some people are far more sensitive than others to poisonous influences; and much greater differences are to be expected to exist between man and reptiles in this respect." Prof. Cook stated the results of a series of experiments which he too had made on frogs. He starved the frogs before administering to them a decoction of potato-bugs, and the effect on the reptiles was to make them very sick.

Chemistry.—A number of chemical papers were contributed by Prof. J. Lawrence Smith. One of these was descriptive of an apparatus for exhibiting the absorption of gases by palladium. The apparatus consists of slips of palladium and platinum; on being introduced into a flame, the palladium-slips coil up like a scroll, while the platinum-slips retain their original form. Another paper was on "Graphite Oxide, as prepared from the Graphites of the Sevier County Meteoric Iron, and DeKalb County Meteoric Iron." Further, he exhibited a pound-weight of cæsium alum. He gave an account of his unsuccessful attempts to obtain cæsium in the pure state. Small particles of the metal were obtained mixed largely with a carbonaceous compound, but they could not be detached from the black mass, as they took fire on being exposed to the atmosphere.

Meteorology.—A new meteorological instrument, designed to measure the effects of various climatic conditions on the human body, was described by John W. Osborne, of Washington. The instrument has a motive power, furnished by a clock, which agitates two pounds of water heated to the temperature of the blood. The water is contained in a paper vessel which permits some evaporation. The water for these experiments was heated somewhat above blood-heat, for quickness in registering and reading. The vessel containing the heated water represents the human body, and the effects of heat, cold, wind, and moisture, can be measured just as they affect the human body, and thus the precise extent of these changes can be registered and formulated.

Velocity of Electricity.—We take from the New York Times the following abstract of Prof. Joseph Lovering's paper on "An Acoustic Method of measuring the Velocity of Electricity." Practically, he said, electricity has no velocity. According to one experiment, when a very long conductor was used, electricity traveled at the rate of 288,000 miles per second. This rapidity is considerably lessened when a shorter conductor is used, and may come down to barely 800 miles per second. For satisfactory experiment, therefore, the longest possible lines should be used. A wire from Cambridge, Massachusetts, to San Francisco, and thence back through Canada to Massachusetts, about '7,200 miles in all, transmitted a message in two-thirds of a second, and some of this time was wasted through thirteen repeaters. Electricity traveled over 4,000 miles of cable in one second, even under some unfavorable conditions. Prof. Lovering's system connects the wire with tuning-forks, the vibrations of which indicate the ten-thousandth part of a second, or even less. The application can be made, however, only by those who are familiar with acoustics..

Transportation of Fish-Eggs.—A recent shipment of salmon-eggs from Glasgow to New Zealand was unsuccessful. The cause of this failure is not known, as every precaution was taken by Mr. Frank Buckland, who superintended the shipment, to insure success. The length of time, says Nature, during which the eggs were packed on board ship was one hundred and twenty-one days, or only nine days longer than the