SCIENCE NOTES.

Otago Witness, Issue 2287, 30 December 1897, Page 48

SCIENCE NOTES.

'.* Scientific contemporaries have' come to the conclusion \ that there is only one' earth, and such being the case, it is a very desirable place of retiderca. An idea prevails in the common mind that our world is only one of countless similar bodies ; that space is filled with solar systems not unlike our own, and that it is possible other globes are inhabited and quite as habitable, if not more bo, than the one on which we dwell. Popular Astronomy says:— "Although our solar Bystem is only one amoDg thousands of systemß now known to exist in every part of the - heav&js, among all these other systems there is not yet a single one which closely resembles our own." This is not a positive assertion that ouis is the only world in which human beings live and move and have their being, bat it leads up to that belief, and this is sustained by much argument dealing with astronomical technicalities which may be omitted her?. Not only is our earth unique in its favourable position in our system, but our system as far as is known is unique in the universe of systems. We rarely think on how narrow a margin we live. A little more heat or a little more cold, and we die. Oar existence depends on keeping changes of temperature within a range of about 1 per cent, of what we know as possible extremes. IE the moon were very much larger the tidal wave would carry the entire ocean twice a day over the surface of the earth. If the earth were much smaller we would lose our atmosphere ; if it were much larger we could not stand upright more than five minutes, nor would we be able to mount a hill except by painful crawling. If the year were twice as long as it is, it is doubtful if we could raise food enough in the summer to carry us through the winter, or if we could survive trie accumulated cold. In every way our earth lies just at the meeting point of two 'kinds of death which "on this bank and shoal of time " we must fight with either hand. It makes no difference whether we have fitted ourselves to the earth through a long process of evolution or whether it was fitted to us ; as far as we know, it is the only habitable opot in the universe, and the

chances are. almost infinite that no other is so favourably located. Let vi make' feha most we can of it.

•. • The leDgth of time dating which tbe bacillus of diphtheria may continue in the throat after an attack of the disease is a matter of the greatest interest, for on it depends to a large extent the possibility of arresting the progreeß of diphtheria by means of isolation. But an even more important difficulty in tracing the origin of infection and in preventing its importation arises from the faot that the bacillus may exist in a state of virulence in the throats of apparently healthy people. A person, for example, who tfappena to be immune to the disease, at any rate for the time, is exposed to infection. The microbes lodge and develop, and remain virulent. No disease, however, is produced, and nothing happens to attract attention to the fact that; this person is a carrier of infection. It is to be feared that it is practically impossible to eliminate this source of disease. Of coarse, the chief means by whioh immunity is produced is a comparatively recent attack of the malady itself. In each cases when the attack is over, but the microbes may remain., in consequence of the patient's acquired immunity he may feel no. inconvenience. The most striking instance of, this condition - is a French case, In whioh^thebacillus was ,' still to be found, at "the-'eii^ ,of 15 months.-. Another case is reported in which^Dr Hew^ lett found the bacillus at intervals during 22 weeks ; and its persistence for three or four weeks after apparent convaleseace is by.no means uncommon. Now it is easy to say " that such cases must not be allowed to mix with other people until their throats have been shown to be free from infection, but a much more serious difficulty looms behind. These immune individuals, if exposed to infection again, may catch it afreßb, and carry it about with them without showing any signs. A case is reported by Dc Foalerton, of the British Institute of Preventive Medicine, in which this sequence .of events occurred, and a consideration of the facts of the case makes it quite obvious how enormously difficult it must be to obtain effective control over an infection which is liable to take root and be distributed in Buch a manner. — The Hospital.

1 . • There are some, says W. T. Stead, who imagine that this age has been destructive of the belief in miracles. In reality it, more - than any other since the world began, has brought home to the average man the stupendous miracle of the world. They call it a materialistic sge, which has chained the soul of man to inert mattex. But almost before the reproach is heard science proclaims that there is no such thing as inert matter— that every- atom- is alive, and. that pur mortal -< bodies are vast composite conglomerations of living organism?, upon whose pitched battles - in. our. veins depend our health or our disease. v To take bqt one instance : Imagine all that' we understand by the word microbe, • and , then recall the fact that the, microbe' was .. practically unknown 60 years ago.'! In- a ', very special fashion science has revealed, to . us a new heaven and a new earth, infinitely marvellous, testifying to an understanding so vast that the mind of man cannot by searching find it out. Behind each discovery that advances our knowledge the infinite unknown indefinitely recedes. We weigh the stars, analyse their composition in the spectroscope ; we photograph the moon and make mspa of the canals in Mare. But, far more stupendous are the discoveries that have been made, not in the infinitely distant abysses of „ space, but in the infiaitesimally smell mole cules which are all aronod. Science has sent its Roentgen ray through the darkened veil and revealed the invisible and summoned all men to enjoy it as their inheritance.

• . • Mr William Tate baa crowned a series of handsome gifts to his fellow-countrymen by presenting London with a palatial building, a National Gallery of British Art, and has furnished it with 65 valuable paintingi, tbe total cost of the noble benefaction being about £200,000. To these pictures have been added a contingent from ' the National Gallery in Trafalgar square, and the" fine collection purchased for the nation under the terms of the Ohantrey be quest. For the first time in the history of British art the student can study that art as a whole, po far ac it is represented by works produced during the present century. The gift, besides being one of f ar-reacbing goodjbp the country, is,a noble example to the rich, showing them, what a r superb monument a generous man can raise , for -himself to keep bis memory green. The . new'galleryl a t very beautiful' building, stands on the banks of the, Thames near Vauxhall, * on the site once occupied- by an~ extremely ugly and gloomy erection which was devoted to a far lass noble purpose — Millbank Prison.

* . * No means are known of producing light without hear, yet, so far as illuminating purposes go, this heat represents waste energy. It was proved by Professor S. P. Langley five or six years ago that the firefly is almost an ideal source of luminosity, for the beat which accompanies the light it emits is extremely small. In fact, Nature produces this light at about one fourhundredth part of the cost of the energy which is used up in the candle flame, and at but an insignificant fraction of the energy required to produce an electric light of the same intensity. Much thus remains to ba done before natural results can be equalled by artificial processes. An investigation of firefly light from another point of view has recently been made by Mr H. Muraoka, of Japan. Three hundred fireflies were captured and placed in a box, at the bottom of which was a photographic plate wrapped in black paper. It was found, that the direct light of the firefly behaved like ordinary light. Bat when . the rays emitted by the fireflies fell upon a piece of cardboard, or upon a copper plate, some filtered through, and these were found to possess the properties of Roentgen rays. The cardboard or the metal seemed to concentrate the glow-worm i rays, and make them capable of piercing various opaque substances. - How this' action " is- produced has not been explained.