SCIENCE NOTES.

Otago Witness, Issue 2649, 21 December 1904, Page 88

SCIENCE NOTES.

— : — ~ ~/ % — Certain scientific men now believe that j .the immense internal heat of the earth * ■knay be, utilised. It is not merely a- que6*ion M getting steam, says Professor Win. There would not be the slightest in obtaining steam" from" the in- , £e"rior of the earth, - because that involvestonly" a little extra labour in boring into (the hot area; hut a- method must be pro- , prided for dropping the .vater to the hot s area'i allowing it time to heat, and yet hay- j Sng.it returned to the surface as steam, with- . •fcut' interrupting the flow. Two holes might fee bored into the earth 12,000 ft deep, and ; "perhaps 50ft apart. There would be a- tern- ! jperature far above the boiling point of ' jwater. Then, "if very heavy charges of • Mynamite or some other explosive were '< lowered to the bottom of each hole and ' jexploded simultaneously, & sufficient connec--%iotf might be established 1 between the two Jiples.^The rock would be cracked! or fissuTed ■in ail: directions, and the surrounding area made into an immense water-heater. The jwater poured into one hole would be turned into steam, which woula pass through the hole to the earth's surface> The Wessute otsuch a column of steam would be enormous, and the' whole operation auto- • ansitio, and the amount of power far beyond present conceptions. , i — It' has 'for some years been known that | sunlight acts as a destroyer of many of 'those pathogenic- organisms which are popularly known as germs. Some time ago an 'ingenious experimentalist demonstrated this fact'in a very convincing manner by pre- ; ■jpaving a "culture" of' these germs on a ' fiat surface and exposing it to sunlight be.aieath a stencil plate, with the result that , iJie obtained an image of the cut-out part »r the stencil in . dead germ life, the rest of the prepared plate being still alive. He ,)called it a "living photograph," but the ' ■fcameterm has since been applied to the popular cinematograph picture. The Massachusetts Board of Health have recently carried out a scries of experiments in order jto ascertain how far sunlight is able to jcleanse water affected with the undesirable kerms which result from sewage contamination. The two organisms dealt with more particularly were the colon bacillus and that "Associated with typhoid. They found that 'l>oth_ species were quickly destroyed 1 by free *coess to sunlight, 3Q minutes to an hour feeing sufficient to sterilise ai culture when "Spr-ead out in a thin layer, as 1 in the photographic experiment already detailed. In the ;jCase of the typhoidl bacillus, from 95 to 99 «>er cent, were quickly killed by exposure to direct sunlight, but there were always a Jew hardy individuals which required for iheir destrueLion an extended time. ~~ Professor Ira- Ber/isen, president of J:he iTohns Hopkins University, U.S.A., contri- ' ijutes a paper on the extremely vital subject of "Scientific Research " to the November number of the Pall Mall Magazine. fjFrorn scientific research," he writes, on by a host of workers all over ithe civilised earth, we are learning more Jiud. mole afcoui th« universe fie live ia* i ;

The mass of knowledge thus gained is in general called natural science, and the different branches of knowledge are called the natural sciences. But science means more than knowledge. It means the gaining of knowledge by scientific methods. It meanß x advancement in the knowledge of the universe. What is the use of it? There always have been those who have asked this question, and th^re probably always will be. There are many who have not had the opportunity to look into the subject, who think that scientific research is of doubtful value, .that the world would 1 be just as well off without it— indeed, many seem' to think that the world would^ be better off without it. It is simply a question whether it is well to know as much as we can alxmt the world we live in. This is a hard question to answer, - but it may- be said that most people agree 'that knowledge is & good thing 1 ., . The more, we know about the world we live in, ~ the more likely we are to live rational, sensible lives. Scientific research is teaching us a host of useful things. What we, know of diseases and the means of ouring them has been taught us by scientific research. Again, we owe to scientific research, most of what we call' the comforts of life. The great "inventions, that play such an important part in our lives to-day are the result of scientific research. It ia rarely the ,case that those who carry on scientific research are the ones who make the great (inventions ;- but they gather the knowledge that makes the inventions possible. This is a, mosf"",important point, that i is often lost - sight .of. [ Short-sighted persons, seeing only that some great invention is made Jby one who does not carry on research/ straightway conclude' that the inven- i tion would ' have been made without re- j search. , But it is clear that great inventions couldl not be made without knowledge, and knowledge is gained by research, and is then made the common property' of mankind. -We come into a. world (bountifully supplied jyith' knowledge. All are free to use it. Let us not forget that we owe ifc to generations of, 'earnest workers who have carried on scienti£c research." — That the time occupied by our world in its " diurnal rotation can, be slowly lengthening is, of course (says the Electrical Magazine), -not apparent to everyone. Seve-ral-natural" physical causes tend to effect the gradual arrest of the earth's rotation about her axis, such as the tides, the for- j imer molten state of the earth, etc. .It "would seem that the immense- energy stored /in the rotation of a. solidl -globe 7925 miles in diameter, with a specific weight five and a-half times greater than water, revolving at aya v maximum surface velocity, of more than 10Q0 miles ;per hour, could never be appreciably absorbed. - By "an interesting calculation, it can be shown 'that this surface velocity may j be slowly, if inappreciably, increased by artificial means. The force stored up in the earth is calculated at 30,333 billion horse-power. To reduce the rotative velocity of the earth's mass "by as little as one second, 10,000 million billions of tons of minerals would need l to be brought to the surface .from a depth of 1500 ft. At present 2000 million tons of minerals of all kinds are annually brought "to th© surface. The energy stored 1 in this mass being raised would require -the comparatively endless time of six billion' years to retard the..earth's rotation by one second The drift from glaciers towards v the equator would, however, • appreciably affect the earth's rotation. The generation of magnetic effects and electric currents from pole to pole, owing to its rotation in a magnetic field caused by the sun's influence, would absorb some of the energy from the vast store represented) by the revolving mass forming our world:. But for the fact ,that other planets" have 'been arrested 1 of all proper motion" in millions of past ages, 6ne might safely consider .that the' length of day will for a long time yet be without change. — A demonstration was given in London a short time ago of a new lamp, designed to burn petrol in conjunction /'with an in-candescent-mantle. The petrol is contained in a metal receptacle placed above the lamp, as~ far away from the burner as possible, andi flows by gravitation to a chamber below the mantle, the supply being regulated by a stop-cock. There it is vaporised, a portion of the vapour being burned in a small jet to provide the heat necessary foxvaporisation, while the remainder, mixed with air, ascends to the burner proper. For starting the lamp there is under the vaporising chamber a little cup containing some asbestos, andi a small quantity of methylatedi spirit placed in this, and ignited with a match, affords the. necessary initial heat to warm the chamber to the temperature at which the petrol becomes vaporised. After this has been done the lamp is automatic in its action. It is claimed that one quart of petrol at s^d will maintain a 150 candle-power burner in action for about 16 hours.— Page's Weekly. — Professor A. H. Thompson, of the Kansas City Dental College, has recently been urging, the importance of the teeth as a means of identification, and 1 as an illustration he quotes the case of the terrible fire some years back at the charity bazaar in Paris, where the sole means of recognition of many of the victims were the records preserved' by their dentists. Such records, he considers, would 1 be of immense service to life insurance companies, and an instance is quoted where identification would have been impossible except by the teeth. Professor Thompson has v - drawn up a suggestive scheme which includes the measurement of the arch ana! vault o£ the jaws; the size, shape, and irregularities of the teeth; including any particulars of artificial interference. The scheme is elaborated in an article contributed; to the Popular Science Monthly Magazine, New York. — It has ben found that moistening seeds before sowing them has a good effect oil germination and growth, but moistened |e.eds are often jßre.red Ufion by parasites^

and instead of moistening with water, it has proved better to steep the seeds for a time in a solution of sulphate- of copper (1 per cent.), and then precipitate the copper, which is injurious to germination. This "sulphatage" keeps away parasites. MM. Breal and Giustiniani have mad© experiments of late to ascertain whether a very dilute solution of suphate of copper alone would serve the< purpose without injury to germination, and their res .s have been communicated to the Aeadeiuy of Sciences, Paris. They left the seeds for 20 hours in a weak solution of sulphate of copper, or blue vitirol (1 to 5 parts of sulphate to 1000 of water), and while still wet dusted them with slaked lime, or even chalky soil, then dried them in the air. They kept well, and yielded a good crop. The best plan is to incorporate with the solution of sulphate 2 or 3 per cent, of fecula, and on _ cooling to mix the whole with four or five times its weight of seed. The seeds are left to steep for 20 hours, then powdered with lime and dried in the air. The grains are thus coated with fecula, charged with hydrate of copper, and plaster. —^London Globe. — Speaking roughly, wo have reason, from the data so far available, to believe that tbft stars of the Milky Way are situated at a distance between 100,000,000 and 200,000,000 times the distance from the sun. At distances less than this it seems likely that the stars are distributed through space with some approach to uniformity. We may state, as a general conclusion, indicated by several methods of making the estimate, that nearly all the stars which we can see with our telescopes are contained within a, sphere not likely to be much more than 200,000,000 times the distance of the sun. The inquiring reader may hera ask another question : Granting that all the store we can see are contained within this limit, may there not be another number of stars without the limit which are invisible only because they are too far away to be seen? — Harper's Magazine.