Page:Popular Science Monthly Volume 9.djvu/663

Rh five to six francs, and there has been a steady decline ever since. In 1870 the price was four francs, in 1871 3.50 francs, in 1872 three francs, in 1873 2.50 francs. There is now a very general disposition to abandon this culture, and since 1872 the amount produced has been growing less from year to year. This decline is also, in a great measure, due to the introduction of new dyestuffs of mineral origin.

Detection of Arsenic in Organic Matter.—Dr. Armand Gautier proposes a new method for separating arsenic from animal matters, and for detecting its presence. By combining the sulphuric-acid and the nitric-acid processes he has obtained very satisfactory results, as regards both the rapidity of the operation and the exactness of the determinations. He first treats the matter supposed to contain arsenic with nitric acid, then with sulphuric acid, and finally with nitric acid again. By the first operation the organic substances are disaggregated; by the second they are destroyed very rapidly, and by the third, with the addition of more nitric acid, the last traces of organic matter are eliminated, while the formation of sulphide of arsenic is prevented. Having made a number of quantitative experiments, M. Gautier never met with a discrepancy amounting to so much as one-tenth of a milligramme between the amount of arsenic introduced and that found.

Timidity of Birds.—Dr. J. G. Cooper, in the Naturalist, comments on the "sociable and confiding disposition" of the birds of the Western United States, compared with the same species eastward. This difference, he remarks, has been noticed by several writers, but the reasons have so far been scarcely mentioned. According to the author, the chief reason is that in the West bird-collectors and idle boys are less numerous, while sportsmen find larger game so plenty that they do not waste ammunition on small birds. Besides this, the prevalence of prairies over most of the Western region makes any garden full of trees and shrubs a rare nursery for the woodland species, where they find more protection from hawks and weasels than in their native groves, while they may also levy a small contribution on the fruits in return for the insects they destroy, and their lively songs. In California, the poison intended for ground-squirrels has also destroyed millions of birds about the fields, and left them unhurt in gardens.

Fattening Oysters.—Salt oysters, on being transferred to fresh water, are "fattened" in the course of two or three days; if allowed to remain longer they become lean again, and are flavorless. Prof. Persifor Frazer, of the Academy of Natural Sciences of Philadelphia, holds that this change cannot be due to an increase of flesh, and attributes it rather to a simple distention of the tissues, owing to the admission into them of a greater quantity of fluid. During the oyster's period of growth on the sea-coast, its tissues are constantly saturated with the ocean-brine; on removing the animal to merely brackish or to fresh water, the conditions are at once favorable for osmose to be commenced. The fresher and less dense liquid without permeates inward more rapidly than the more saline and denser liquids within escape, and the effect is to swell the tissue, as a cow's bladder half filled with air and immersed in a vessel of hydrogen is swollen, or still more nearly like the swelling of a bladder half filled with copper sulphate when immersed in water. "It is worth while to inquire," adds Prof. Frazer, "whether means could not be devised to effect this fattening while yet not depriving the oyster of the salty flavor which is its chief charm to many consumers. Perhaps an immersion in concentrated brine for several days and its subsequent removal to ocean-water would suffice."

"Shooting-Stars."—We make a few selections from an interesting paper on "Shooting-Stars," by Prof. C. A. Young, published in the Boston Journal of Chemistry. These shooting-stars, he says, are very small, for the most part weighing certainly not more than a few grains, and possibly only some thousandths of a grain mere particles or cloudlets of dust, which are traveling in space under the same laws as those which govern the motions of the planets and comets, and with a velocity as great. Their least velocity is more than thirty times that of a cannon-ball. When they encounter