THE POPULAR SCIENCE MONTHLY.
ble (as M. Panthier suggests), as the missionaries to China made known the fact more than a century ago that the Chinese had suspended bridges, that the ideas may have been taken thence for similar construction by European engineers.
The Spectator, in its notice of M. Touchet's work, "The Universe," says: "Man generally flatters himself that his anatomy is about the highest effort of Divine skill; yet that of the insect is far more complicated. No portion of our organism can compare with the proboscis of the common fly. Man can boast 270 muscles. Lyonet, who spent his whole life in watching a single species of caterpillar, discovered in it 4,000. The common fly has 8,000 eyes, and certain butterflies 25,000. M. Touchet treats it as an established fact that so fine are the sensory organs of ants that they converse by means of their antenna? Consequently the strength and activity of insects far surpass ours in proportion. In the whole field of natural science there is nothing more astounding than the number of times a fly can flap its wings in a second; it must in that point of time vibrate its wings five or six hundred times. But in rapid flight we are required to believe that 3,600 is a moderate estimate."
The following, according to Prof. Palmieri, are the signs of an approaching eruption of Vesuvius: When the crater tills up and the vapor from it diminishes in quantity; when the vapor from the crater yields a heavy deposit of iron or sodium; when the water sinks in some of the springs of the neighborhood. The phenomena more nearly preceding an eruption are, the occurrence of earthquakes, increasing in intensity and frequency for some days beforehand; also the irregularity of the diurnal variations of the magnetic needle. One of the remarkable attendants of an eruption is the frequence of lightning flashes accompanying the condensation of vapor of water from the crater; just as in an ordinary thunder-storm lightning occurs at the time the vapor is condensing, as is proved by the rain that follows.
Prof. Muir has been investigating the effects of various saline solutions on lead by suspending pieces of bright lead of of known area, each in a solution of known composition, for a given time, and then estimating the amount of lead dissolved, by Wanklyn and Chapman's color-test. He finds the greatest solvent power exerted by solutions of the nitrates, ammonium nitrate being especially active. The carbonates, as was before known, have the greatest protecting power, and next to them come the sulphates; so that, when either of these are present, even if the water contain a considerable proportion of nitrates, the solvent action on the lead is very slight.
It is well known that all alloys containing copper, even in minute proportions, are readily acted on by acids, which makes them dangerous when used for household utensils. M. Helouis has proposed an alloy, under the name of platinum bronze, which is entirely inoxidizable. It is a nickel alloy, prepared from nickel made thoroughly pure by various processes and maceration in concentrated nitric acid. The proportions employed are nickel 100, tin 10, and platinum 1 the two latter metals being added to the fused nickel in the proportion of 4 of tin to 1 of platinum, and the remaining six parts of tin added subsequently. For bells and sonorous articles the proportions are slightly varied, viz., nickel 100, tin 20, silver 2, and platinum 1.
M. Renault has lately brought to the attention of the Paris Academy of Sciences a simple and effective method for reproducing drawings. The drawing is first made with sticky ink on highly-glazed paper, and afterward dusted with bronze-powder. Sheets of sensitized paper are then pressed upon the former, when the lines of the drawings are reproduced upon the paper by the chemical action which takes place between its sensitive surface and the metal. Impressions may be taken at any time, by softening the ink on the original with vapor of alcohol, and then redusting with the bronze-powder.
Sulphuric acid, according to Dr. L. de Martin, when added to the sweet juice of the grape (must) in the proportion of from fifteen to forty-five grains of the concentrated acid to twenty-two gallons of must, exerts a favorable influence on the process of fermentation. The process is hastened and rendered more complete, and a better and more beautiful color is given to the wine. Analysis shows no more sulphuric acid in this wine than in samples not so treated. When the must is alkaline, as it sometimes is, the process of fermentation produces lactic acid instead of alcohol; hence the utility of sulphuric acid, which sets up the alcoholic fermentation of the sugar.
Dr. Virchow has been experimenting with reference to the influence of coal-gas on vegetation, when diffused through the soil. He finds, after a long series of carefully-conducted researches, that coal-gas is an active poison to vegetation, trees, shrubs and ornamental plants, being killed by it when it is allowed to permeate the soil about their roots.