SCIENCE NOTES.

Otago Witness, Issue 2695, 8 November 1905, Page 72

SCIENCE NOTES.

— The modern conception .of the atom occupies a prominent place in Professor j George Darwin's -"address, to the British Association in South Africa. J Dalton's atom, Eolid, indestructible, eternal, and, as the •word implies, indivisible served the pur- { poses of" i he .chemist for. iorig.,' But thej growing needs', of science -'have' 1 , rendered:' this old idea of the atom obsolete. - liecent investigations, ,' especially ujgeonneefcioii ! frith the radio-active" elements, "nave* made a new conception imperative. Lord-Kel-vin's visor .shadowed forth the ides' -that perhaps ttvj atom was not necessarily indeitruetible. According to his conception, in fact, it was merely a sort of motion, a whirlpool, in die all-pervading, ethsr. Hence there was nothing theoretically impossible in an atom ceasing to exist; this merely implied a cessation of the motion an the ether which formed it And Pro-, lessor Ovookes^- long ago suggested that atoms mighi p.'iss out of existence in the -centres of overgrown worlds. The most •recent idea of the atom is a somewhat complicated one. In the first place it is no ,'onger an atom at all in the strict sense of the word — it is no longer indivisible. This is necessitated by "the supposed spontaneous change of radium into helium. Sic Oliver Lodge has <x>mpared' ihe modern atom to a swarm of bees, from which in- j dividual be« 3 may fly away from time to ! time. The helium produced from the ! emanations of radium would be represented by the bees flying away from the swarm. The smaller particles " which form the atom of radium escape and form the atom of helium, of which the structure is supposed -to be less .complex. These smaller particles composing the atoms are -known) < as electrons, and it is computed thai; the hydrogen atom contains some 800 of Jthem. 'And the elements', with higher, atoniio | weights contain more in" proportion to their greater 1 weights. Thettatom to' which j Professor Darwin calls special attention in ! his address .-is the conception of Professor j J. J. Thomson,- This atom is supposed to ■ consist -of a 'large number of corpuscles, ~or -electrons', which may be 'described as par- i ticks tof negative electricity. And it is paradoxical, though true, as Professor Darwin points out, that it is easier to count the number of electrons in an atom than the number of atoms in a portion of matter. Th«s& negative particles of .electricity (the electrons) " repel each other, but are kept together in the atom by a positive electrical charge, or something equivalent" thereto. That these electrons exist in the atom, and that • they are moving "~with a ' .velocity comparable with that of light — ,viz., 200,000 miles a second — Profe/sor Dar- ! ■win regards as certain. The mechanism ' fey which they are held together in groups, lie admits, is hypothetical The model which Thomson suggested as representing the atom was a globe charged with positive electricity, inside which there are some thousands of corpuscles of 'negative electricity revolving in regular orbits with great velocity. By mathematical reasoning ■he has shown that such an atom would possess mechanical and electrical properties aimulating exactly some of the most fundamental properties of the chemical elements. —•London Globe.

— Discussing further the origin of life,' (Mr Butler Burke, of the Cavendish JJaboratory, Cambridge, in the Fortnightly Review. points out' that by spontaneous generation he means the "development of what we have a right to think is 'living from that which we have hitherto had a right to think was not." Proceeding to describe his experiments with radium en sterilised bouillon, Mr Burke remarks that ihe microscopic bodies evolved are decidedly unlike both bacilli and crystal?. The ''radiobes," to give them their new name, undergo many developments. After cix or sevon days, and at times even less, they develop nuclei ; but later still they

cease to grow, and then begin to segregate and multiply. These are some of the qualities which have led Mr Burke to suppose .that -they are assimilative and automatic, and '< not, strictly speaking, lifeless things., "Thus," he says, "the gap, apparently insuperable, between the organic and the inorganic world seems, however roughly, to be bridged over by the presence of these radio-organic organisms, which at least may give a clue as to tie beginning and the end of life;" —An Italian inventor, named Dobelli, has thought of a very ingenious method of saving a large -percentage of power in petrol motors which up to now is lost with the pressnt form of cylinder. He argues that in ihe usal type <he greatest lompression takes place at the moment the piston is at the top of its compressing stroke, and as ,at this point the piston is whart may be called its "dead" position, when the charge is fired the explosive force is not properly utilised instantaneously, because it has first to overcome the point of inertia. 'When the piston passes this point on its real 1-ower-givinsf movement, the initial" force of . the explosion has much diminished. Dobelli's Idea, is that a second, and opposed, piston made to operate in such a manner by cams that it advances at the same pace as the other retiresi keeps up the Tull compression, so that when the ignition. ;s; s brought into action just as the power piston is beginning its working stroke r.he fullest force of the explosion is obtained. Dobelli states i.hat he has actually made an engine on the lines of his theory, and finds that it gives an efficiency of more than twice that of ordinary engines with a consumption of petrol of only ore-quarter as much. The supplementary piston is also made to alm<st meet the working piston on its exhaust stroke in order to expel practically all the exhaust gases, this result not being obtained by ordinary engines. If this invention becomes a fully-established fact, says the World, an immense stride will have been made tovards the ideal motor.

—It is very often said of any new invention of great commercial importance that it :s destined absolutely to supersede the- method which has hitherto held the field against all comers. Bu*. it frequently happens that the old device acquires a new character before undreamed of, whi?h gives it strength and vitality to enable it still to resist the onslaughts of its younger rival. Thus gaslight was threatened with extinction by electricity even as the candle has been extinguished by gas; but the Welsbach mantle came to the rescue and the situation was saved. Now, when the omnipotent steam — the great power of the nineteenth century — must needs look to ita laurels lest they be wrested from it by the gasoline motor, the turbine brings timely help, and the doom of the steam engine remains a very long 1 way off. The turbirje steamer Virginian has crossed the Atlantic in 100 hours, beating the record from Britain to Canada by nearly 20 hours When it is remembered what a very great increase of power is represented by quite a small gain in speed of a vessel through water, it will be understood that this saving of 20 hours is a veritable triumph for the turbine.

— "Within comparatively recent years — that is, since aniline dyes have almost completely supplanted the mineral and vegetable dyes formerly used in colouring cotton textiles, an extensiv-s demand for castor I oil has sprung up in the industry of dyeing and! printing cotton goods. The general "principle underlying the utility of this oil ia colouring processes is that the aniline and alizarine dyes are soluble in sulphurated castor oil; in other neutral fats and oils these dyes, with few exceptions, are in, general insoluble. In certain, processes of dyeing and printing, therefore,' castor oil enjoys a practical monopoly over all other oils.

— "The question," Says the Lancet, "is often debated whether physiognomy is a growth of vocation or whether it shows

that the vocation chosen is in accordance with the particular capacity and ability of the person to whom it belongs. In other words, if the barrister does not show the 'legal face,' the aspiring priest the 'ecclesiastical face,' the medical student the 'physicianly face,' the soldier the 'military face,' and so on, is that a sign that they have mistaken their calling? Is the marj who 'doesn't look a bit like a doctor' likely to fail because his physiognomic qualification is wanting? Or will he, whatever his original features, gradually come to acquire the type of the profession to which he belongs? The answer to the question is, of course, that both theories are right. A certain kind of face, the socalled scientific face, is so often seen among modem medical students as to prove that the owner of that cast of countenance is likely to adopt medicine as a career. Conversely, whatever the original cast of features a medical man may have possessed, the anxious, delicate, and absorbing work of medical practice will put a stamp upon them."

— The phrase '"Thunder clears the air" is familiar to all, yet we are told that even scientific men did not know its full meaning until just the other day. Details are given in Mr J. Cx. Macherson's "Meteorology" of Sir Benjamin Richardson's experiment with the rnia?, and we read: — " Before a thunderstorm everything has been so still for days that the oxygen in the air has been to some extent robbed of its life-sustaining power. The air foete 'close' ; a feeling of drowsiness comes over all. But after the air has been pierced by several flashes of lightning the life-force in the air is restored Your spiriis revivr>, you feel restored, your breathing is far froer, your drowsiness is gone. Then there is a burst of heavenly music from the exhilarated birds." After the passage of lightning; through the air ozone is produced — the gas is product after a flash of electricity. "It is a kind of oxygen with fir.c exciting effects on the body." We sho-ild all be grateful, then, for the occasional thunderstorm.

— The Medical Press: — "Though the introduction of chloroform and ether marked one of Ihe greatest and most beneficient revolutions in surgery, there are few surgtons whose hearts will not be gladdened when they ars relegated' to the limbo of forgotten things, and some simpler, safer, and less distressing drugs take their place. The pharmaceutical field has been carefully searched for new ansesthetics, but in spite of certain agents of minor utility, such as ethyl-chloride, having been unearthed, chlorcforra and ether are far trom -being superseded. It seems, however, that scopolamine, an alkaloid of scopola, which has hitherto been known as a mydriatio and sedative, can be usefully employed for general anaesthesia. Terrier, of Paris, _ reports that it can be given, preferably in association with morphia, so as to produce insensibility lasting as long as nine hours. The patient during this time appears to be .in a profound sleep, but though he can be roused by shaking; and shouting, complete insens-'bility to pain exists. When the effect wears oft he wakes as from sleep, has no knowledge of what has occurred — even if an operation has been performed in the interim — and is free from all adverse symptoms. The appetite is unimpaired, and he can enjoy food. The best method of administration is by hypodermio injection — in combination with morphia. One milligramme i. injected with a centigramme of morphia four hours before the operation, another similar injection is given two hours later, and a third after one hour more. The only drawback to this ideal method of inducing anaesthesia is that the drug is not always successful, and profuse sweating sometimes follows its use. If these disadvantages could be obviated, seopolamine would seem to have a rare future before it."