SCIENCE NOTES.

Otago Witness, Issue 2009, 25 August 1892, Page 43

SCIENCE NOTES.

— In the course of a series of lectures delivered by Professor M'Kendrick before the Royal Institution of London, the speaker showed some interesting experiments to demonstrate that there was in reality a distinct electrical action of the human body. He showed the effect of animal electrical purreuts by means of a very sensitive galvanometer. Currents from animals such as the torpedo fish had long been known, he said, but it was much disputed whether there was such a thing as an electric current from man. This man-current he demonstrated by putting his hands into a three-quarter per cent, solution of common salt contained in two fiat vulcanite dishes. Ihe effect upon the galvanometer was greater as the number of fingers inserted was increased, aja<i v greatest when the muscles of the ar**" aS contracted. There wero oq fe 1*"1 *" j* we ,5® species of animals that \?er* ".. .■ ortlian °y batteries, the speaker ' . llv , in S *\ ecl ™ only five or ife wer» ■ *« tared, altnough —Th A - - generally known. tricalphV Urr ' iaßoreali ff r is^ rly an elec " oour6'* -omenon says Mr J. Monro in the yf, - -of an illustrated paper in Cassell's -agazine, The magnetic needle is disturbed | during the display, especially if it be a brisk

one with violent streamers; the telegraph lines are rendered unworkable by the strong " earth "or induced current in them. Telegraph instruments are sometimes actually fused, signal bells rung on railways, and even an electric lamp has been kept lighted by these vagrant and irresponsible currents. Moreover, it has been demonstrated that the period of maximum display of the Aurora recurs every 11 or 12 years, and coincides with the observed maximum period of spots on the sun's diso, and of magnetic storms or perturbations in the earth's magnetism. Such periods occurred in 1870-2 and 1881-4, and another has been anticipated during the present and two following years — an anticipation which seems to bo correct, as the Aurora was seen from near London a few weeks ago. There is evidently, the writer continues, a connecting medium between the atmosphere of the sun and the atmosphere of the earth, which may be called the " luminiferous ether." Some Auroras, however, appear to be quite local in origin and effect, the electricity being developed by meteorological changes.

— A metallic alloy, closely resembling gold, which has a fine grain, is malleable, and does not easily tarnish, is described in one of the technical journals devoted to the jeweller's art. The process for producing this alloy is as follows: — Pure copper, 100 parts, is melted, and to this are gradually added 14 parts of tin or zinc, six of magnesia, 56 of ammonia chloride, 18 of quicklime, and nine of cream of tartar. This mixture is melted and stirred in a crucible for half an hour, after which it is kept in the molten state for another like period. Tho dross is then removed from the surface, and the metal poured into moulds.

— A purer chloroform than has yet been available, by virtue of its purity, is claimed to be produced by the Swiss scientist, Pictet, by a process of artificial refrigeration that precipitates a quantity of deleterious impurities. It is moreover claimed that the physiological effects of the impurities removed by Pictet's process when isolated have been such as to show their deleterious quality beyond doubt. If this be all as stated, the use of chloroform in surgery, the benefits of which are eimply incalculable, may become free from some dangers hitherto attending its administration. The use of intense cold for purifying and separating chemical substances is still in its infancy, though for the extraction of menthol and similar substances from essential oils it has been for some years employed.

— Four electric fans have been placed by the Crocker Wheeler Company in the turrets of the powerful iron vessel Miantonomah; the intention being that they shall blow away the smoke from the guns.

— According to Mr Thomas Fletcher, of Warrington, who replies to a correspondent in a scientific contemporary, glass cannot be cast as a metal is cast ; it cannot be made sufficiently fluid. The so-called castings are made by compressing glass heated until it is in a plastic condition in metal moulds. The moulds are expensive to make, and the glass requires the most careful annealing, usually for from three to seven days after it is moulded.

—An electric device for clearing a track of obstructions is among the newest ideas. It consists of a triangular steel folding frame over which a net is stretched. This is placed on the front of a locomotive and can be opened at will, catching the obstructions upon it. An additional arrangement is a scoop to drop on the track. The recent tests were very satisfactory-

— A fine instance of the usefulness of photography in astronomy has just been furnished in connection with the appearance of a new star in the heavens. From time to time stars appear and disappear, and it is of great interest in connection with the development of worlds to be able to follow the career of such stars from the moment of visibility ; but without the aid of photography it is a matter of the mere3t accident if a new star is seen as soon as it appears ; but whon it is once noticed it is only necessary to inspect the photographic plates of the region of the sky in which it is situated as far back as they can be got from the date of noticing to get information as to the earliest date at which the new star was strong enough to affect the plate, and the rate at which it increased in brightness. A new star which was first recognised as having appeared in the heavens on February 1 was found by Professor Pickering " to have left its mark on a photographic plate of his as far back as December 1 of last year ; the plate had seen and recorded the appearance of the star nine weeks before all the astronomers in all the observatories of the world knew anything about it.

— In a recent lecture on " The Venomous Snakes of India and the Mortality caused by them," Sir Joseph Fayrer said that although the chemistry of snake poison had been much studied of late, no antidote to snake virus had yet been found. Remedies were of little avail when the full effect from a bite had been produced; but when the poison had entered the system in smaller quantity, medical treitment might be of some service. The poison can neither be Bucked from a bite nor swallowed with impunity. After naming the different snakes found in India, of which th,3 cobra is the most formidable, the lecturer pointed out that the average loss of life for the eight years ending 1887 was nearly 20,000 human beings, and more than 2000 head of cattle yearly. To reduce this alarming death rate hq thinks that the best plan will be to make more fully known the appearance and habits of these dread reptiles, acd to give a re^ I ward for each poisonous snake killed, 9" proposal to cat down and clear, &W iie jungle in the vicinity of yiUaji*^ - 7 tao thinks, hardjy be expected * j could, he desired effect. "* produce the

In some "Nafe&a *■ British Jsjes, 5*5 * v* ° n the Climate of the reputation "' uich serve to keep up the interns* 1 • jL Longman's Magazine for an Mn .- *ag science article, Mr E. H. Scott -arks that the averages of a number of years show that noon is the finest part of the day, while in many parts— notably, those inland, there is a decided tendency to wet in the afternoons in summer. This phenomenon of wet afternoons is very decided at Continental stations, such as Prague, Sfc. Petersburg, Vienna, Modena, and Coimbra in Portugal. In all these places an afternoon maximum, as regards frequency of fall, is perceptible. The afternoon thunderstorm in tropical climates is a well-known periodical visitant. On our west coasts, such as at

Valencia, no afternoon maximum can be traced, and the wettest hours are in the early morning. The practical result of the whole inquiry as regards our own comfort is, says Mr Scott, that it is wisest, if we can, to take our outing before lunch. In treating of rainfall Mr Scott advises that, to secure the driest possible residence, a spot should be chosen with hills lying to windward on the rainy side. His references to the rivalry of different health resorts as to records of sunshine and temperature are amusing. — The multiplication of electric installations for commercial purposes seems at last likely to have some effect on the wider and more scientific use of electricity in the treatment of disease, for it is possible now in most large cities for a doctor to have at his command at a Btnall cost a far more powerful current than is yielded by ordinary medical electric appliances, and he can reduce this according to his requirements. Of course the field of application of electricity is limited, but hitherto the disinclination of doctors to bother with appliances they did nob understand has kept it too restricted, and let the use of electricity pass largely into the hands of quacks who use it for all sorts of cases where it can do no good but only harm; where electric current can be turned on as easily as water or gas, its use in ordinary practice must increase.