128 



THE POPULAR SCIENCE MONTHLY. 



blc (as M. Panthier suggests), as the mis- 

 sionaries 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 con- 

 struction by European engineers. 



NOTES. 



The Spectator, in its notice of M. Tou- 

 chet'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 compli- 

 cated. 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?. Con- 

 sequently the strength and activity of in- 

 sects 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. Pal- 

 mieri, are the signs of an approaching erup- 

 tion of Vesuvius : When the crater tills up 

 and the vapor from it diminishes in quanti- 

 ty ; 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 oc- 

 currence of earthquakes, increasing in in- 

 tensity and frequency for some days before- 

 hand ; 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 ac- 

 companying the condensation of vapor of 

 water from the crater ; just as in an ordi- 

 nary 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 contain- 

 ing 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 plat- 

 inum, and the remaining six parts of tin 

 added subsequently. For bells and sono- 

 rous articles the proportions are slightly va- 

 ried, viz., nickel 100, tin 20, silver 2, and 

 platinum 1. 



M. Kenault has lately brought to the 

 attention of the Paris Academy of Sciences 

 a simple and effective method for reproduc- 

 ing 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 draw- 

 ings are reproduced upon the paper by the 

 chemical action which takes place between 

 its sensitive surface and the metal. Impres- 

 sions may be taken at any time, by soften- 

 ing the ink on the original with vapor of 

 alcohol, and then redustiug 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 fer- 

 mentation. 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 care- 

 fully-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. 



