SCIENCE NOTES.

Otago Witness, Issue 2541, 26 November 1902, Page 64

SCIENCE NOTES.

♦-The appearance of a "new Btar" has in fell ages been felt to be an impressive occurrence. The constellation groupings are 50 permanent in their character (says Knowledge) that to .fies of a sudden some old amiliar pattern among the stars changed in ia features by the sudden appearance of a iew member — a star like the other stars md not a planet, for its place undergoes no .-hange — is co at variance with our ordinary experience that it is no wonder that our forefathers regarded such an event as partaking of the supernatural. In the times before the telescope — indeed we might go further and say in the times before the ipeotroscope— such an event brought no information with it. It was impressive, it excited curiosity, but it conveyed scarcely kny lesson. The spectroscope examination pf "new stars," on the other hand, has been wtraordinarily fruitful, though we are very Ear as yet from being able to fathom the exact; meaning of the facts which we have ibserved. Ope thing is clear, namely, that xxlies appearing so suddenly as "new stars" lave always done, and fading away again IO quickly, must differ entirely from the preat host of permanent stars. Yet we :annot but feel that the changes through nrhich a "new star" may pasß in a few reeks, and the order in which those changes lucoeed each other, may throw much light ipon the changes which have marked in ;he past, or will mark in the future, the life-history of the more stable members of the heavenly host. It is this thought trhich makes the watch for "new stars" of such importance. They offer to ue a key, which, however imperfect, is th* only one nrhich we can hope, to find to unlock the secrets of etelar evolution. ' _ Lord Kelvin has calculated that the 1 freight of . the universe is equal to 1000 million suns. On account of the attraction 1 >f gravitation every object in the universe 1b in motion. The heavens look calm on fc fine night, but in reality every star is in rapid motion through space. Lord Kelrin's problem, was to find how much material- substance the universe must contain in order that the mutual attraction between its different parts should produce the star motions actually observed, assuming the stars were once at rest. He took as the imits of our universe a distance such that :he light of the most distant star would take about 3300 years to reach us, though the. rays travel with c, velocity of 186,000 mile 3 per second. The conclusion at which Lord Kelvin arrives is that, if a mass of natter equal to 1000 million tuna were at rest in this almost infinite extent of space 25 million years ago, and was uniformly distributed through it, the different parts prould by this time bo moving on the kverage at about the rate actually measured py astronomers. In other words, reasoning from the present velocity of stars in ppace, Lord Kelvin shows that the amount pf matter in our universe is about equal pn mass to 1000 million suns. As there lire probably not more than 100 million stars which can bo seen or photographed, it follows that there must be ten times as much dark material in the universe as there is bright. —In the Popular Science Monthly Prolessor -Woodward discusses the progressive cooling of the earth and its relation to the length of the day. Whether the day was formerly shorter than now, and whether it ,will,be longer in future, depends upon the max of the earth, for meteorological dust toonstantly falls upon the surface and inicreases the quantity of matter. Laplace concluded that there had been no sensible tehange in the length of the day for nearly £000 years. Repeating this calculation with new data, Professor Woodward finds that '.he day has not changed so tittch as half i eccoad djftUfiff tb& lift 2,0 ttftlieu yean

after the beginning of the solidification of the earth's material. When the cooling of the earth is finally determined, the change will.be marked. Prof. Woodward finds that the ratio of the change by day to its initial length is two-thirds of the product of the loss of temperature multiplied by its cubical contraction. If the primitive temperature of the earth, for example, was 3000deg C, and if its cubical contraction was that of iron, the day will be finally reduced about 6 per cent. ; that is to say, about one hour and a-half. In order to bring about so pronounced _a change, an enormous lapse of time is necessary. About 300,000 millions of 3 r ears, according to Professor Woodward, are required for a 95 per cent, contraction to take place. After the expiration of one million millions of years the length of the day will not be sensibly affected. — Professor Garbasso, Turin, desci-ibes in the Nuovo Cimento his experiments on the action of sunlight, even diffused sunlight, in facilitating the passage of electric sparks. The light doubles or trebles the number of sparks which can pass across the gap in darknese. The effect of the light continues for a little after the light is out off. Focussing the light on one or other electrode, especially the negative one, gives a continuous current. Screens of mica, glass, or alum solution check the action of the light, but plates of quartz or Iceland spar permit it to pass. Professor Manuelli thinks that heat, not ultra-violet rays, is the cause of the phenomenon. — Some statistics as to the use of alcohol as an illuminant are given by M. L. Denayrouzo in the Bulletin of the French Physical Society. This use of alcohol, first proposed in Germany, a few years ago, has recently been rendered practicable from a commercial point of view by the introduction into Franco of methylated spirits, and also by an increase in the efficiency of the Denayrouze lamp. Taking 1.08 grams of pure alcohol, or 0.64 grams of curburetted alcohol (alcohol carbure) per candle hour as the consumption of this lamp, the cost is estimated at 0.00478 and 0.00298 of a penny per candle hour for these two alcohols, as against 0.01428 of a penny for petroleum. The lamp consists essentially of a, wick, conducting the liquid by capillarity into a chamber, where it is vaporised, the necessary beat being produced by a copper bar which derives its heat from the lamp itself. The vapour passes through a small channel into a kind of Bunsen burner, above which the mantle is fixed. The series of operations is entirely automatic. —It has already been stated that Mr Perrine, of the Lick Observatory, who now has more than a dozen discoveries to his credit, saw, on September 1, a new comet of the ninth magnitude. Not many astronomers devote themselves to this line of work, which is one requiring exceptional patience, and is not of a kind that is done systematically at the Government observatories, so that there are probably a large number of these vagrant celestial bodiei which visit our system and go away unnoticed. Nearly 800 entries are extant in the lists of observed comets, of which about half wore seen before the invention of the telescope in 1609. Since that date, therefore, there have appeared on an average three or four per year, but a very small proportion of those were bright enough to be of any popular intereet. When a eflmetsoeker makes a find he circulates the details of his observation, which enables obseivatoriee to rr"a-nre the position of the objert as o]tiv><- ti™s of clear iky occur — in the present c !-,*• ;l>c- comet »as recorded on a photographic plate exposed at Greenwich recently — and fiese observations are combined to compure the oibit. Unless this be an ellipse, which is the ca=e le=<» than once in four time=, immediate interest in the gaseous body has generally expired by the time its rath is determined, as it has then usually vanished from cbscriatioii. — Daily Telegraph. —At tiit» nioshitts fit t&>4 JEtutilh Aakmua*

tion in Belfast, on September 15, Mr J. Milne, F.R.S., delivered in the Geography section an interesting address on worldshaking earthquakes, with special reference to the recent volcanic eruptions in the West Indies. Mr Milne said that the greater number of the worst earthquakes occurred in the deepest parts of distant oceans, but their world-shaking effects were often visible in enormous subsidences of land. Indeed, in one case about a hundred miles of coast line in Japan had been through this cause raised no less than 3ft. An earthquake in Assam a few years ago moved about 10,000 square miles of country. When an earthquake occurred at the bottom of the sea its effect on the surface was to cause huge waves, which sometimes rolled along in vast volumes for thousands of miles. He believed thai small earthquakes had no relation to volcanoes, though they might have a cumulative effect, but world-shaking earthquakes had often produced volcanic action. Nearly all volcanoes were comparatively near the sea, for steam was their motive power, and that steam was generated by water, at great depths, percolating into the baee of mountains towards the intense seat at the centre of the earth. It was mostly in high mountainous regions descending steeply to adjacent deep waters that great oceanio and seismological changes took place. The greatest mountains were not on land. We called the Himalayas big because we could see them, but there were ridges and ranges quite as great in the depths of the ocean.

—In the Quarterly Journal of Inebriety for July last, Dr A. MacNicholl, of New York, publishes an account of a family m which the results of degeneracy and disease, arising mainly from alcoholism, have been traced for four generations. The first generation comprised a married couple of good social position. The man was a well-to-do and respectable merchant of English parentage, while his wife was of Huguenot descent. Both took wine habitually. They had two daughters, each of whom developed in early life a fondness for wine and spirits. The elder of the two died a raving alcoholic maniac at the age of 40. The second daughter married a wealthy banker, and had a temporary mental breakdown at the age of 35. She bore eight children. The two males grew up to be drunkards. Of the six daughters five died from phthisis, between the ages of 20 and 35. The- surviving daughter married a man of good position (healthy and a moderate drinker), became a drunkard and an opium-eater, and ended her days in poverty. Of this union 17 children were born. Ten of the 17 children died from phthisis below the age of five years ; of the seven surviving children, the eldest, a female, became a concert singer and female prize-fighter, and led a drunken life. The second, a male, became a moderate drinker, and showed signs of phthisis. The third, a male, was a moderate drinker, and showed suicidal tendencies. The fourth, a male, became a habkual drinker, and ended his life at the age of 35 by an overdose of morphia, taken whilst drunk. The fifth, a female, married early, took to drink, and developed suicidal mania. The sixth, a male, at 12 years was an industrious and studious boy, but peculiar in his ways; at 16 a moderate drinker; at 23 a confirmed drunkard; at 28 committed suicide. The seventh and last member of this unfortunate family was a male, who received his education in a high school, and who at the age of 21 years ,?as the subject of moral perversion and suicidal impulses. — Condensed from the Lancet.