SCIENCE NOTES.

Otago Witness, Issue 2672, 31 May 1905, Page 68

SCIENCE NOTES.

- — Next to aneurism, the great value t>i X raya is seen in cases of pulmonary consumption.- In the first place, a. careful examination of an affected chest at intervals during -the course of an illness may iiot only be of great interest but also of iSrreat use, as an additional means of indicating ihe course of the disease; and in the second lilaoe, in the very early cases — the merely suspicious cases, indeed'— an X-ray examination is essential. It has been proved beyond all doubt that marked radiographic jobanges. from normal, suggestive of tubercular disease, have now been found when 'lonly the merest suspicion of phthisis has existed; when no so-called physical signs ib.ave been detected; when no tubercle (bacilli have' been found in tne sputum, if vthere was any of the latter to be obtained ; (when the only symptoms giving rise to lanxiety have been some ill-health, loss of .weight, and perhaps cough and dyspeptic (troubles. It is a serious matter to urge, Jaay, a business man, with much depending fcpon him, to throw up everything and go through several months of open?air treat- . pient on a vague suspicion alone; it is Jstill more serious to put off doing this until tarequivocal signs have developed, and it may be too late. Badiography, in these jcases, is now invaluable.— Scientific Amerijean. — The latest annual report of the- Local Government Board contains the record of some investigations carried out by Dr M. Gordon to determine the effect which speaking has in polluting the air with M-Icro-organisms. The natural character of <ihs saliva as regards bacteria was first exafmined;, and a. certain minute form was found extremely abundant, the number vary iing from 10 millions to 100 millions in about jfcb.3 sixteenth part of a cubic inch. Dishes *- joontaining a solution by which minute jfcraees of saliva could be detected were then jplacedt'at varying 1 distances from a speaker, jand by examining them " subsequently, the \ idistance to "which particles were carried ! ffrom Tvs mouth was determined. It was found that tliese particles 'were present fin the air no less than 40ft in front of a loud speaker and 12ft behind him. The Jntults would be alarming if they referred »o malignant forms" of bacteria; and even as they .stand they suggest that an audijence may be literally infected by the words •jpf a speaker. The extent to which" *pe«.oh^ anay pollute or enrich the air may thus fin future be decided by a. bacteriological —A. 'new form of incandescent lamp -in which vaporised petroleum spirit is used iuts been devised. The principle "of the invention, is a petroleum spirit vessel placed »t a higher level than the burner. From ifchis vessel the gasoline gravitates through & Itube to a control -raJve, which regulates Hhe flow of the volatile liquid into a. generator, where it is vaporised through being 9i«ated by a, separate flame. The gas then passes through a needle valve, receives its «orrect proportion of air, and is then Bgnited in a burner fitted with an ordinary fincanctescent mantle. An intense light is jjrodueeit To start the lamp the vaporiser has to be heated, and this is accomplished by the ignition- of a little methylated spirit poured over asbestos contained tin a tray placed below the needle valve. ZFhe petrole'un consumption of the lamp .frith the maximum light vis very economical, vme quart of spirit being sufficient (accordfing to the Scientific American) to give lightof 150 candle-power for 16 hours. Though <t£e inherent dangers attending the use of petroleum are by no means obviated in this device, it constitutes an. excellent lamp for outdoor use; — A British engineer, writing in Indian ■ {Engineering, maintains that "the much•.dvertised superiority of American manufactures over British is a pure myth, and jfche credit- it has gained, both in India- and / Great Britain, is due almost entirely to the i Jftction of alarmist statesmen at Home and the press — technical and newspapers. Our j Bte-tesmen and. political leaders have done j touch to depreciate British manufactures ■both at Home and in the eyes of the foreigner by making- ill-considered speeches (pointing out to the world where we are Jpehind our competitors. Not one-tenth per joent. of these men are competent to judge, tond get their information from the press, land the press re-copy what the great men say, with the result that an atom is quickly i magnified into a whole mass. What wonder that foreigner discounts British manufactures when the leading men of Great decry their own people, and give *he foreigner what he is pleased to regard .as -an honest warning, and -as he •wants the best he promptly goes where IBritain's great men say he will get the best iln my opinion great credit is due to Major ißa'bington, superintendent of the Cordite OPaetory, for the manner in which he resisted Ibeing led away by this clap-trap of American superiority; for so persistent has been )this clap-trap that to order anything in Great Britain is almost regarded as tempt- j ] Sng Providence, and the thanks of the whole British race in India should be ac- | fccrded him for his publio statement that, , '. isinee his visit to England on deputation < an connection with the CSordite Factory, ; 'he believes still less that it is necessary &o go to America for electrical apparatus, itnd that the BritisE manufacturer can more .than, meet his American competitors.' It is a fact which the Government of India ' should specially note that one of their ] officers has exploded the fallacy of Ameri- * can superiority, and I am sure they would 1 realise greater satisfaction if it were an ( , -instruction to all officers who go home 6 'on, deputation that they mu&t get British- ' 1

manufactured articles, or else furnish Government with strong r«asons why such articles cannot be satisfactorily procured in Great Britain. Fully 95 per oent. of the machinery installed at the Cordite Factory is of British manufacture, and I am sure it must be very gratifying to Major Babington to know that his confidence in the British manufacturers has not been misplaced, for there has not been a single item of British manufacture which has not more than fulfilled its guarantee." — One of the most remarkable provisions in Nature for scouring the ' uniformity of the composition of the atmosphere is that by which the sea fakes from the air any excess, of carbonic acid — technically, carbon dioxide — or supplies any deficiency. The airount of carbon in the atmosphere in this form is very small, there being only three volumes of carbonic acid in 10,000 of air, and yet Liebeg showed that the atmoJ sphere at this rate must contain at least i 3081 billion pounds of carbon, an amount greater than is to. be found in all the plants and in all the coal mines in the world. Dr A. Harden, in a communication to j Nature, points out that if mankind were i to go on burning fuel at the present rate for 1000 years — supposing our coal to last so long—the percentage of carbon dioxide would bo doubled, and this would mean a poor look-out for humanity, say, 10,000 years hence, when the race would end by general suffocation. To prevent this the sea comes , in. Before the proportion, in the air rose i even one-tenth, to 3.1 volumes in 10,000, , the ocean would absorb the gas as fast as it was produced. Besides which, carbon dioxide is continually being absorbed by J rocks and soils, and it is the food of all plant life. — A German physicist, Herr Liebenow, puts forward the theory, which has been hinted by others, that there may be enough radium in the crust of the globe to account for the earth's internal heat. It is only necessary to suppose; for this object, that radium is "uniformly distributed throughout the mass of the earth in quantities of about one-thousandth of what is known to occur in pitchblende." But there are many Indications- that radium occurs more frequently than this in all known rocks, and that its occurrence is more frequent near I the surface of the earth than in the in- • terior. "This theory," the Electrician observes, "demolishes a£ a "blow all our conceptions of a, liquid interior at the tremendous- temperatures implied by a uniformly rising gradient. It now becomes 'permissible to assume that the temperature rises towards the centre of the earth, but attains a maximum ait no very great depth, and that the interior beyond that point is at a uniform and comparatively low temperature." — Daily the conventional barriers between one science and another are being broken down. Notably is this true in the case of I medicine. The British Medical Journal, for instance, has lately published papers by Mr Frederick Soddy, Sir William Ramsay's brilliant assistant, on the possible inhalation of radio-active gases in cases of pulmonary disease; and by Professor Karl Pearson on the statistics of anti-typhoid inoculation. Tropical medicine, again, has lately discovered the enormous importance of insects in the conveyance of disease. (Ifc may be noted that bacteria are not insects, but unicellular vegetable organisms.) Many bacteria and other immediate causes of disease are habitually conveyed from the sick to the sound by insects. The reader is familiar with the most celebrated case, which 1b that of malaria, and to which may be added yellow fever, sleeping-sick-ness, the tsetse-fly disease of horses, anthrax, and other maladies, including two which affect birds, and which first led Sir Patrick Manson on the right track in the discovery of ihe causation of malaria. Now that / insects,, like the mosquito, are found? to be of such malign importance in the conditions of life in tropical countries, it is plainly necessary that the study of them in these relations be no longer left to medical men, who have sufficient problems of their own to unravel without spending time on all the subjects more or less germane to medicine. Quite recently a well-known physioist, under the auspices of the University of Manchester, delivered a special course of lectures on radium and its phenomena to classes of doctors and medical students. In this connection it is hardly necessary to remind the reader ihat the gieatest name in the history of medical science since Harvey is not that of a physician at all, but of a French chemist. — C. W. 8., in the Pall Mall Gazette.