THE POPULAR SCIENCE MONTHLY.
of adulteration to which the fabric is subjected is enormous. Although linen is often used, the favorite adulterator is jute, which is cheaper, is heavy, and so easily takes the dye, and in other ways is made to simulate the silk, that it is the more difficult of detection by an unpracticed eye. If a sample of the "goods suspected to contain other kinds of fibre be treated with hydrochloric acid of 1.13 specific gravity, the silk will be dissolved, while other kinds of fibres, such as jute and linen, will remain undissolved."
Opium-poppy in France.—The cultivation of the opium-poppy in France is steadily increasing. It now occupies 50,000 acres, of the value of 4,500,000 francs, yielding opium to the value of 2,000,000 francs a year. Different samples of opium, raised in various parts of Europe, are said to have yielded from 8 to 13 per cent. of morphine.
The Volcano of Santorin, when last visited, in October, 1871, had ceased giving the small eruptions which had been common almost without intermission since the great eruption of 1866, and the summit of the crater, covered with great blocks of lava, presented the same appearance as in 1707. A little steam was still escaping, but this seemed due almost entirely to the vapor of water condensing on the cinders covering the cone. In the north the fumerolles were still active, and all around the stones were covered with sulphur. At the southeast point the volcanic activity had not completely ceased, but had greatly diminished. All this would show that the eruption had entered on its last stage, and after a period of great central activity in 1866-'67, accompanied by a diminution of activity in 1869-'70, it is now again assuming a condition of rest and quietude.—Nature.
Colonel Weitzel, of the Brussels Congress, tells of a village on piles, still inhabited, on the island of Noessa Kimbaugan, off the south coast of Java. Its inhabitants live by fishing. On being asked by Colonel Weitzel why the village was built out into the water, one of the inhabitants said that it was in order to be secure against the attacks of tigers.
English Sparrows in Australia.—Complaints are received by the Royal Horticultural Society that fruit-crops in Australia have been seriously injured by the English sparrows imported into that country.
The dolmens, or cromlechs, of Algeria, was the subject of an address by General Faidherbe before the Brussels International Congress. He considers the cromlech to be a monument indicating a place of interment, and thinks it has no other purpose. According to him, the area in which cromlechs are to be found extends from Pomerania to Africa. That none exist in Belgium he accounts for by the great density of the population, the cromlechs having been there cleared away.
We take from the Journal of the Franklin Institute the following facts in microscopic photography, contributed by L. Erckmann: Thin sections of plant preparations laid overnight in aniline red solution came out thoroughly colored. When washed in water, the nitrogenous parts retain the red, the non-nitrogenous giving it up. But, if the solution is too concentrated, the image, seen through the microscope, will be red throughout. As the red rays have but little action upon silver iodide, a positive print will show very dark in the nitrogenous, and lighter in the other portions.
In Great Britain and Ireland there are about 30,000 coal-mines, yielding 120,000,000 tons per annum. The depths from which this coal is raised vary widely—the deepest workings being the Dunkinfield and the Rosebridge collieries, near Wigan. The depth of the latter is 2,418 feet, and the average temperature 95° Fahr.
We have in the Gardener's Chronicle a remarkable instance of the luminosity of fungi. The spawn of some unknown species of fungus, growing on a trunk of spruce or larch, was found to give a perfect blaze of white light along the track where the trunk had been dragged. The light was enough to read the face of a watch, and it continued for three days.
Attention has lately been directed to a new method for printing on cloth, the invention of Mr. E. Vial. The fabric to be printed is first impregnated with a solution of nitrate of silver, or other metallic salt, which, when brought in contact with zinc or copper, will be reduced to the metallic state. The patterns are designed on zinc or copper, and, wherever contact is made between the metal plate and the cloth, a metallic precipitate is firmly fixed upon the tissue. If nitrate of silver is used, the color of the precipitate, and therefore of the cloth, may be varied by varying the strength of the solution, from a brilliant gray to a deep black. The color withstands acids, alkalies, or soaps.
The sewage of Tunstall, in Staffordshire, England, is to be converted into cement by precipitation, by the process of Major-General Scott. This system is already in operation in Birmingham, West Ham, and Ealing.