SCIENCE.

Daily Telegraph (Napier), Issue 3057, 13 April 1881, Page 4

SCIENCE.

In a recent lecture on the photophone, in London, Mr A. Graham Bell mentioned what he called an interesting fact for a physicist to follow up. He said the experiments made by himself and his friend, Mr Sumnev Tainter, showed that all substancos in the form of thin sheets emitted sounds when exposed to the action of an intermittent beam of light. Nearly every material tested produced sounds varying only in degree. Among them were paper, carbon, pine wood, cigars, and even tobacco smoke. The sounds are supposed to be due to molecular changes effected by the luminous ray. This view is confirmed by the fact that a feeble musical note was obtained from sulphuric ether, the experiment npon that liquid being performed at the suggestion of Professor Tyndall. A theory of planetary influence upon the great weather changes of the earth has been advanced by Mr R. G. Jenkins, E. R. A.S., who thinks there is some disturbing influence akin to that commonly attributed to the waxing and waning of spots on the sun in the perturbations of the earth effected by the planet Venus in cycles of eight years. Mr Jenkins calculates that the great waves of cold which sweep over the earth occur, on an average, once in eight years. He also traces a connection between each arrival of the planet Jupiter at perihelion and the occurrence of .an unusual heat wave every twelve years. A test of these theories by reference to past meteorological records in Western Europe does not tend to confirm their correctness.

According to Mons. Boussingault, the French physicist, the practice of boiling the mercury with which barometers are made is a mistake. He says the presence of a trace of air in the chamber gives the mercury a desirable quality of mobility. The same member of tiio Paris Academy of Sciences has lately presented to that learned body a paper on the thermal springs of Venezuela, one of which is described as the second hotest in tho world, being surpassed in temperature only by a hot spring in Japan. Mr Alfred R. Wallace says in his new treatise on insular life that wo find no indication that the almost perfect similarity in tho animal world. The fact that the climate and vegetation of two countries are alike does not justify the conclusion that you will find the same animals in each ; nor does the fact that the same animal is found in two different countries justify the conclusion that the clmates and floras are alike.

A fellow of the Royal Microscopical

Society writes to tho English Mechanic that the continued demand for cheapness in mauuments bas done serious injury to nvrr" 1 -- copy. Students' tsUmris, ho says, have become commoner and commoner until the construction is only a little better than that of patent locks. Another source of injuryis the exportation from the continent of Europe of large numbers of rubbishy Luiscs. These, fortunately, can be detected, fvom the fact that no optician will put his name to them.

Tho Copley Medal of tho Royal Society of London was awarded at the annual meeting to Professor James J. Sylvester, the distinguished mathematician, now a member of the faculty of the Johns Hopkins University in Baltimore. It was bestowed in recognition of his extensive ancl profound matnematicalresearches, especially those relating to the theory of invariants and covariants, modern geometry, and the theory of pure numbers. The phylloxera insects in the south of France appear to be unfavorably affected by the weather which has recently prevailed there, and hopes are entertained that the vineyards will suffer less than usual this season. A remarkable propensity Jof the young insects to seek the light has lately been observed by Mons. Fabre. Possibly this might be availed of to facilitate their destruction.

A recently published German treatise by Mr A. Keferstein, of Erfurtb, on tho development of lepidopterous insects (moths and butterflies) contains a notice of poisonous caterpillars, from which it appears that tbe hairs of some species are really stings with a poison gland at the base of each. In the course of the discussion now going on concerning the possibility of preventing frogs in London, or at all events reducing their opacity and persistence, attention has been called to the historical fact that in 1783 a fog covered the greater part of Europe for nearly two months.

The preference for iron instead of wood as a material for railway sleepers becomes more manifest in Germany everr year, and the change from, wood to iron is being made on many lines as fast as the sleepers already laid wear out.