SCIENCE NOTES.

Otago Witness, Issue 2722, 16 May 1906, Page 68

SCIENCE NOTES.

— The problem what foods are mest su ; t able to /nan's needs, and in what quantities has been made the subject of experiments by American investigators on themselves, tbeir colleagues, and students, which resulted in the two-fold conclusioa that we eat too much meat and take, generally speaking, too much food. The experimenters, led by Professor Chittenden,^ of Yale University, for several months, and in some cases for more than a year, reduced their meat diet by one-half, and yet maintained as *good or better health; the muscular power of the athletes was increased, and mental activity undiminished. Strictly scientific examination of the problem in America-, - Germany, and France has always led to the same judgment, that health and strength can be kept up w : th a much le&s proportion of nitrogenous food than meat-eating . peoples deem necessary. The distinct teaching of science is that, excepting the very poor, most persons eat about twice as much as they require, and that the superfluous amount is not merely wasted, but is a cause of-illness and euffering. The rice-eating Japanese and Chinese practically confirm the scientific doctrine. — Sir James Colquhoun, of Luas, is interested in- r tne. discussion in which naturalists -have lately been indulging over tVe vendaoe of- Loch 'Maben. He . remembers 4he- attempts made by his father to cultivate the spawn of this curious little fish in the trout-rearing ponds near Rossdhu. The late Sir James Colquhoun insisted tbat the vendace of Loch Maben and. the powan of Loch Lomond are one aud the same species; and, further, that, they are in reality descendants of the deep-sea herring — in which opinion, by the way, he was borne out by no less an authority than the late Frank Buekland. The theory is that there was -once tidal iommunication between these lochs and the ocean, and that in the- long course of the ages colonies of herfmg found themselves enclosed in fiesh-water. lakes, and adapted themselves to their changed circumstances. Certainly, both the vendance and the pow,an behave in a way suggestive of herring* ancestry. They are always found in shoals, and within, the whole memory of fishers they have never been persuaded to take an angler's lure. By nets, and by nets only, can they be caught.

— The ~ Countess of Warwick has some remarks in the March Fortnightly Review, which urgently need all the. emphasis that can possibly be lent to them (writes "C. W. S." in his "Scientific Notes" in the Pall Mall Gazette). The point which in one place she- makes is that it is- the later years of education which are mott productive of profit. From one standpoint, the fundamental argument against childlabour in aAy shape or form ia humanitarian. We cannot but feel in our heart of hearts that the thing isa scandal to our kind. But in these notes the standpoint must be, at anyrate primarily, scientific. Let us, then, consider this question of the years of education — or,- to speak more - accurately, of schooling— from' Ihepoint of view of the psychology of childhood. There are many methods by which it may be 6ought to answer the question raised. One, for instance, is Lady Warwick's, and consists in making the observation that the countries whose industrial competition we have to fear are not, let us say, Italy or Spain, where child-labour is abundant, but Germany and America, where child-labour is much less prevalent. The writer says: — "Our deadliest competitors are not thosa who rely, on immature and untrained labour, but those who best equip their workers for a place in the nation's workshops. If cheap and immature labour were a source of successful competition, we might at . once bow our heads before the rivalry of Russia, Italy, Spain, and Turkey. As a fact, it is America, Germany, and industrial Switzerland against which we are measured, rind it is in these three countries that the elementary school age is highest, most vigorously enforced, and technical and secondary education most available at Ibe end of the elementary course. In the canton of Zurich and in eight Ame dean States the compulsory school age has already been raised to 16 years. 1 ' There is overwhelming evidence, continues Dr Salceby, that disaster 'ollows the attempt to school children between the ages of three and five years. The evidence is experimental, and also a priori. It is derived alike from physicians, anatomists, schoolmasters, and women inspectors. In Germany and elsewhere, striking but wholly-to-be-expected fcuccess has followed the practice of somewhat postponing a boy's attack upon the classics, and most especially upon Greek.

— The zodiacal light consists of a very soft, faint column of light, rising from the western horizon shortly after twilight. In these latitudes we can see the phenomenon in the autumn in the morning, and in the spring in the evening 6ky, the light rtally extending in the plane of tho ecliptic on both sides of the sun. But when il»e course of the ecliptic nearly coincides with the horizon, the feeble light is extinguished by the great thickness, of the atmosphere through which the light has to pass. Nearer tho equator, the zodiacal light ci»n be seen nearly equally well all through the year. What the zodiacal light is or what causes it are matters to whicb no certain answer can be given. Some observers have asserted that its spectrum consists of a single line in the yellow, and therefore indicating an incandescent gas. Others i>elieve the spectrum to be continuous, and, if this be confirmed, we should be led to tho conclusion that the phenomenon of the zodiacal light is due to reflected sunii^nt, probably from an immense cloud of meteors filling up the space between the earth and the sun.— Liverpool Post.

—Dr Geoige J. Fieher, of New York, th<? secretary of the V.M.C.A. Athletic League, says the rapid growth of towns and cities has resulted in a marked physical deterioration of tho people. So great is this deterioration that in the United States it has been found that there »s a difference of 6in in height in the boys who begin life early in factories and offices in the city and those who were kept at school until they were well towards manhood. A Government commiasion in Scotland fcund that the different in height between city dwellers as a whole s.nd tho-c who lived in the country was 4in, the latter being sft lO^in and the former 6ft 6>>m. In the United States 59 per cent, of the men examined for the army had failed. The£3 facts show that physical training is a necessity in the city life of to-day. The difference in height is only an indication oi tha difference in vitality, and that is

naturally indicative of 9 general change in a man's condition. There are very reliable statistics to prove that in the cities of the Old World a family noi crossed by country blood 16 stamped out in three generations. Th-e trouble is that in cities we live too artificially. We do not get the air, nor the sunshine, nor the icst the country people get, and our bodies are not yet adapted to do without these. The place of physical training is to step in and relegate man to his physical environment.

—An interesting paper on the s-übject of tubes— that part of the boiler which gives the most trouble — appears in a recent issue of the Iron Age. The author refers to a statement by Lieutenant Parks to the effect that they had tried everything in the United States nayy — charcoal, iron, hofdrawn steel tubes, cold-dra»vn eteel tubes, Bessemer steel tubes, and open-heaith 6teel tubes — without finding a material that was satisfactory. The use of an iron-nickel alloy, with 30 per cent, nickel, provides a, material that gives great satisfaction. The French first made hign percentage nickels in lffi)B. ■ They .have been adopted in the French -navy, although the complete tests are not given. Tubes containing about 25 per cent, nickel have" been thoroughly tested By- Mr Yarrow, and his conclusion is that "'a boiler' would require to be retubed two and one-third time* aa often with mild steel tubes as it . would with nickel-steel tubes." He subjected the tubes in his test to the action of acids of fire and of super-heated steam. Tho British Admiralty" has treated similar tubes under boiler conditions, and the results are said to be in support of Mr Yarrow's conclusions. With 30 per cent, nickel tubes welding is possible, and this is evidenced by the fact that- many short - pieces of this alloy have been welded to ordinary steel tubes, to act as " safe ends" and pass through tho flue sli-e^te Here their elastic limit, which is greater than that of ordinary eteels, enables them to stand much better against the expansion of the flue sheets. The special features of these tubes are their non-eorrosiveness. increased tensile, strength, and greater life compared with ordinary steels. — Daily Telegraph.