SCIENCE NOTES.

Otago Witness, Issue 2561, 15 April 1903, Page 64

SCIENCE NOTES.

One very important piece oi information * regarding tKt celestial bedies (writes Dr William Lockyer, Professoi of Solar •Physics, South Kensington Observatory) •was unobtainable nearly a century ago, in, epite of all the resources at the disposal of the astronomer at that period. Of what substances svas the sun composed? Were £he jtar. made of the same kinds i materials as the sun? What was the composition of the nebulae which form such beautiful objects in large telescopes? Such questions had, however, to remain un- ■" nswered, for even the biggest telescope was of little avail. Modern astronomy, ar Ahe "new astronomy," began now to dawn, and 't k this that we hear co much about at the present day. It commenced first oi all -with the discover^ of tho fact that if the light emitted or scar out by any radiuting body-rfiuch as, for instance, a coloured ■flame from the sun or even a star — be illowed to pass through a small piece of glass ehaped in the form of 8 prism, the subBtancei involved could, under observation, be at once detected. The instrument by which this principle is carried out is known as ». spectroscope, which enables the astronomer to investigate the composition of the heavenly bodies. In addition to this most important and valuable friend of the modern astronomer, the process of photography was * little later introduced, and it i» due to these two powerful astronomical discoveries that most rapid advances have been made in almost every branch of astronomy. Ifc .will at once be seen how the application of ttese new instruments of research, revolutionised this 6cicince. Astronomers who had sor years and years beeD carefully obeerving, calculating, and checking the posi■Aions of the ~»tars in the heavens, a process which is very tedjoiis and slow, were now' able to utilise the properties oi the sensitive film with their telescopes-, and eecure (the*- positions of hundreds "or even thousands of stars at one exposure. Such «. survey of the heavens has on a small scale been completed eeveral times over, while on a large scale it is now 'n progress >r en international basis. The photographic plate possesses another very important feature in •that it is capable or recording what the human eye, even when aided by the finest optical means, nijl never be able to see. Fafnit 6tars which have never been observed can be easily photographed and studied, while the nebulae in the bcavens, which were considered s\>% limited in extent and number, are now found to be almost boundless and innumerable. Indeed, one seems to feel more and more an immense admiration for those early workers who so honourably, toiled and plodded in making such a vast collection of observations which tiow, by the methods of the "new astronomy." can be so quickly and so accurately secured. Thus, for instance, 'r. the plact> of drawings of the *olar surface to record daily the eizes, shapes, number, and positions of the spots, photography accomplish^ in seconds what oreviously at times took an hour or so. During total eclipses of the sun the delicate tracery of solar corona can be beautifully and faithfully recorded several timec over in the ehor' time thaJ* is available on "uch occasions, where provioufiy it was quite impossible to obtain so complete a reoord. Our satellite, tho mcon, also, which has been so dcsely studied • and drawn from Ihe timo of the invention of the telescope, Is now Icing magnificently portrayed on x laree pc.il° undci every condition oi illumination. Just as the camera replaces the eye at tho end of s telescope, so can it be employed a f the eye end of a spectrocopo. whether tliw instrument be used in the laboratory for examining the light sources of -.übs'riticcs wp know something about, or in connection with a telescope for analysing the bodies.

— The old auestion as to ib* alimentary

value of alcohol is discussed very fully by the leading medical specialists of Paris in. the Revue. The result of the inquiry is very much what the average man might have anticipated. There is a strong universal condemnation foi such liqueurs a 9 abaioithe or vermouth; while the general opinion of Jhe faculty is in favour of a. moderate use both 1 of wine and of spirits, provided that these can be got unadulterated. A helping hand is given to the semi-teetotal movement by this report. All the doctors interviewed declare against the use of spirits, either diluted or otherwise, except after a meal. — Pall Mall Gazette.

—At the recent annual congress of the, Swiss Society of Natural Sciences, held at Benne, a new and interesting theory as to the origin of the appearance of the higher atmosphere, which is popularly styled as the "blue sky," was advanced by M. Spring, a well-known scientist of Liege. Hitherto the azure tint has been 6upposed o be due tc the refraction of light uron minute corpuscles disseminated in the air. M. Spring, however, has onceived a new explanaticm of the phenomenon. He has carried ou' a number of experiments with luminous rays under almost all conceivable conditions, injecting them int> agitated solutions, and intoa- glas? tube containing pseudo solution.' such as chloride ot aluminium of absolute limpidity; but although he could obtain red, yellow, violet, etc., under no circumstances could he obtain blue, until by the use of electricity he secured a perfectly pure atmosphere in which blue was clearly discernible. M. Spring, therefore, concludes that the blue of tho sky is purely electrical in origin, and is an essential quality of the air.

—In a letter addressed from Eustis, Florida, to a New York contemporary. Mr Sydney C. Haley writes: — "It has long been a matter of speculation with me just v;hy. a rain will help plante so much more- than any form of artificial watering- The popular theory is that when water is applied to vegetation by the latter method, the heat of the sun causes a kind of steam to form, which Foorchee it. This is obyicui'ly incorrect. My own conclusion, which I reached some time ago, and which may, for all I know, be the accented srientifio explanation, is that rain stimulates the plants on which it falls because it ia charged with electricity, and thai the mere wetting of a nlant ha« little effect on it. A few weeks ago I was reading :n your journal, I believe, cf an experiment that confirms mv view, md incidentally usrgest? an idea which, if carried into execution, might prove or immen ccc c value. It appears tLafc some experimenter pa«sed a current through pome pote in which plants were growing, with the effect that they howed ? decided gain in size and fertility over thcfse similarly situated, but not so treated. The difference, if I remember aright, was 40 per cent. Tsow, why would it not do to apply water electrically charged to tho vegetntion, and thus stimulate, as (nearly as rou!d bo, nature's method? The watei could be plar»ed in a vessel from which the electricity could not escape, an insulated barrel, for instance, or a pnil bottomed with rubber or gla«s. After *he water was charged, it could be applied with the aid of an ordinary rubbci h^ti", with a non-con-ducting nozzle ; and that would be all that would bo necessary. Xow, lam not an electrician, sad have not thp mpans of trying this experiment myself, but if~6omo experimenter would follow my suggestion. I believe discoveries of great practical value might b"* mndf." --

—Dr T. Glover Lyon, physician to the City of London Hospital of Diseases of the Chret, ha=> recently issued a namphlet entitled "Venti!".t : on for Crowded Places" : and as we (Chambers's Journal) have had an opportunity of se«inpr the system in action, we are able to testify to its mprits. The method may be thus briefly described : Air. warmed by elcotrin radiators or by hotwater pipe-?, is forced into the rcom to bo ventilated by mean* oi a iunhuL instead

of entering the apartment directly, which would give rise to draughts, the air is let in through perforated screens, the apertures of which are so arranged that where the pressure is greatest the openings are contracted. By the adoption of this device the air is evenly distributed throughout fhe room. At the other side of the apartment the vitiated air is drawn out by means of exhaust-fans, so that there is a continual circulation and constant change of atmosphere. The system is eminently adaptable for the use of hospital wards, where it is the practice to allot a certain number of cubic feet of epaoe to each paticait. It is obvious that if in such institutions an efficient system of ventilation were installed the number oi patients could be trebled or even quadrupled, to the very great benefit of suffering humanity.

—In his Christmas lectures at the Royal Institution Professor Hele-Shaw dealt with "Locomotion — Past, Present, and Future," and he indulged in some interesting speculations'regarding the ejectrio railways of the future and the possibility of utilising some of the world's water power for the supply of electric current. He prophesied a great future for the "Lightning Mono-Railway," the invention of Mr F. B. Behr. Electric tramoars were found in every large city of the world. London, having obey the laws of motion of all ponderous bodies, was moving in the same direction, but* was behind many smaller oities. The lecturer then dealt with the eoureo of power in nature which hitherto had, to a prreat extent, been untouched. Ho showed slides of the great Niagara power installation. Here were 20 5000-horse power twin turbines supplying current for various purposes over considerable areae. The horee-power available was some 10 millions, but at present only 100,000 was used. The* Victoria Falls, on the Zambesi, were twice as high as Niagara, and twice as much water came over the falls. The available horse power all the year round was some 35,000,000; yet all this power was running to waste. Some day it would be used to supply electricity, and then electric railways would spread all over Africa. In conclusion, the leoturer reminded his hearers that the great Farraday, who had co often delighted juvenile audiemces in that theatre, had been the first to discover the mutual conversion of work and electricity by means of electro-magnetio induction.