Popular Science Monthly/Volume 18/January 1881/Notes
A Holtz frictional electric machine, said to be the largest ever made in this country, has recently been constructed by a well-known firm manufacturing physical and chemical apparatus in this city. The revolving glass disk is forty and the condensing stationary disk forty-six inches in diameter. It is provided with the continuous charging apparatus of Van Brunt, which is a very considerable improvement over the ordinary means of charging by rubbing a disk of vulcanite with a skin by hand. The machine gives a discharge over twenty inches long, and, on account of the facility of charging, can be satisfactorily worked in almost any weather.
At a late meeting of the California Academy of Sciences, Mr. W. N. Lockington read a paper on fishes, in which he states that of three hundred and eight species, mostly marine, occurring on the Pacific coast, all but thirty-seven are found in California. Of the five hundred and forty fresh-water species known in the United States, but thirty-seven are found in that State.
That ants can make themselves heard as well as felt, is asserted by Mr. S. E. Peal, who writes to "Nature" that he has observed in several varieties of this insect the power of producing distinctly audible sounds. Two kinds of ants, one brown the other black in color, could be heard a distance of twenty or thirty feet, the noise being produced by scraping the horny apex of the abdomen three times in rapid succession against the dry leaves of the nest.
Dr. Ephraim Cutter describes in the October number of the "American Monthly Microscopical Journal" an interesting study he has lately made of the central surface-waters of several ponds and lakes in Massachusetts. He found, contrary to the general opinion, that the waters in the middle of ponds or lakes contain large numbers of microscopic forms of both vegetable and animal life.
The experiment of irrigating the lands at Genevilliers with water from the sewers of Paris appears to be working successfully. In answer to protests which have been made against applying a similar irrigation to the forests of St. Germain, the engineers say that the apprehensions that have been expressed on the subject are exaggerated. Many buildings have been put up at Genevilliers since the sewer-waters were taken there, but the inhabitants have never been sick. Moreover, since the prevailing winds are from the west, places lying east of the irrigated district should be the ones most troubled with the infection if there were any; but no complaint has come from Clichy, which is thus situated, while the barren tracts on which it looked have been converted into a fertile plain.
The French journals tell of some perfectly fresh meat that became phosphorescent. Some cutlets of raw pork shone so brightly in the kitchen that it was possible by the aid of the light to tell the time by the watch. The butcher from whose shop they came said that all the meat of which they were a part of the stock became phosphorescent within a short time after having been put into his cellar. The phosphorescent meat did not otherwise differ in aspect or odor from common meat; it had not been exposed to a temperature of more than 50°, and entire freshness seemed to be a condition of phosphorescence, so that when the meat began to smell it ceased to be bright. The phosphorescence generally disappeared on the sixth or seventh day.
M. L. Cruls has communicated to the French Academy of Sciences notes of observations which he has made at the Imperial Observatory, Rio Janeiro, on stars unfavorably situated for observation from the Northern Hemisphere. Some of these stars appear to possess a slow but well-defined orbital motion, amounting in some instances to about six degrees retrograde in forty-three years. They have been observed heretofore only by Sir John Herschel at the Cape of Good Hope, and by Captain Jacob at Poonah, India, and it is from a comparison with their observations that he has deduced the fact of motion.
The Royal Society has this year awarded the Copley Medal to Professor J. J. Sylvester, at present occupying the chair of Mathematics in Johns Hopkins University.
M. de Lesseps has a plan for the civilization of Africa by telegraph. Stations for entertainment and for scientific purposes are to be established at points between the coasts and the interior. Thus a party has already arrived in the Oussagura to establish a station to be connected with Zanzibar, and another party has been commissioned to establish a station on the Ogove River to be connected with the French colony at the Gaboon. The stations are to be connected by telegraphic wires, the planting of which will be preliminary to the building of railways, so that these wires, says M. de Lesseps, will become for Africa, as they were across our Western Plains and are for Australia and for the Russians in Central Asia, real conductors of civilization.
Professor Henry Draper writes in the November number of the "American Journal of Science" that, "during the night of September 30, 1880, I succeeded in photographing the bright part of the nebula in Orion in the vicinity of the trapezium. The photographs show the mottled appearance of this region distinctly. They were taken by the aid of a triple objective of eleven inches aperture, made by Alvan Clark & Sons, and corrected especially for the photographic rays. The equatorial stand and driving clock I constructed myself. The exposure was for fifty minutes. I intend at an early date to publish a detailed description of the negatives."
M. Abel Pifre has succeeded, by changing the form of the reflectors and the heaters, in considerably increasing the efficiency of the solar engines invented by M. Mouchot. While M. Mouchot has not been able to utilize more than fifty per cent, of the heat of the sun, M. Pifre with his improved apparatus makes eighty per cent, available for use. With a receiver of 9·25 square metres and a clear sky he boils fifty litres of water in less than forty minutes, and obtains an additional pressure of one atmosphere every seven or eight minutes.
It is proposed to make use of the hydraulic constructions and machinery at Airolo and Goeschenen for the maintenance of electric lights in the St. Gothard Tunnel.
A rock-drill run by electricity has been devised by Messrs. Siemens and Halske of England. It consists of a rod of steel-headed soft iron which moves through three coils of insulated wire; the middle coil is traversed by a constant current which magnetizes the rod, and the other coils are traversed by alternating currents which attract and repel the rod with rapid movements.
"Nature" chronicles the death of Dr. Hofrath von Wagner, Professor of Technological Chemistry in the University of Würzburg. He was born at Leipsic in 1823, first taught in Nüremberg, and was the author of a standard work on chemical technology, translated into English by Professor Crookes in 1872.