SCIENCE UP TO DATE

Evening Star, Issue 15537, 6 July 1914, Page 2

SCIENCE UP TO DATE

MISCELLANEOUS RECENT ADVANCES. LXXXIII. [By James Collier.] [Special Bights secured by -the ' Star.'] —Pacific and Atlantic Coasts. — The two greatest masters of physiography in onr time, F. F. Von Kicht-hofen and Edouard "Sraess, have each propounded, and almost in the same year, en original theory of sea-coasts. Published Tn 1388, Von Eichthofen's theory has obvious merits as an exhaustive classification, bat it need not occupy us at present- That of Professor Suess, put forth a year earlier, has found wide acceptances ainl has been adopted in the admirable series of geographical text books issued by Messrs Whiteombe and Tombs. It can be concisely stated. The class to which a coast-line* belongs is determined by its origin or its relation, or absence, of relation, to the adjacent mountain chains,, The coast-lines of the Pacific Ocean—both the greater part of the west coast of America and the whole of the east coast nf Asia—are bounded by mountain chains that are more or less continuous; and the trend of the coast-line is determined by the trend of its backbone. All such coasts belong to the Pacific or concordant type But there are many other coastlines that have either an opposite relation to their looimtain chains—they may cut across them—w else they have no relation at all. Such are the coasts of Europe and Africa—indeed, of all Africa *ave in the Mediterranean, and those of Arabia and India. All such coasts belong to the Atlantic type, and are either discordant with their mountain chains or neutral.

—A Defective Classification.—

•So long a» only the coasts of the Old World and the" New were taken into account Sueaas theory appeared fairly correct, thoogh the eastern coast of Asia, especially China, hardly answers to the deseripKOfi. But- when the still newer woiH of Australasia came to be geologi-

tally examined it was found that there was nothing in the island-continent or in New Zealand that answered to the main chain of the Andes. The classification mast be reformed. Professor Gregory has undertaken the task. In his 'Geosraphy of Victoria* (1900) he had unreservedly accepted Stress's classification. He is now persuaded that, in order to meet the difficulties created by the western Australian coast* and those of New Zealand, some unessential modifications must be made in the definitions. Otherwise there are no coast-lines anywhere in the world that answer to those cf the Pacific type. In a memoir contributed to ' Scientia' in 1912. which was received at the time with approval in England y and is now incorporated in his recent work on the nature and origin of fiords, the Glasgow professor makes three corrections of some importance in the German professors definitions of the Pacific type. —Defects Corrected. — 1.- The direction of the folding of the earth's crust is a. secondary feature. 2. The parallelism tiefrween mountain chains and the adjacent coasts must not be too rigidly applied. We must be content with a parallelism between coasts and folds and fractures. 3. The parallelism between the coasts and the grain of the ocuntry must also not be too strictly construed. The New Zealand coasts are universally accepted as representatives of the Pacific type, hut there are exceptions in them, and we muat allow for other such exception* in China and Eastern Australia. These modifications made, Suess's definitions may still be adopted. —Fossil Dragons.— The finds of the gigantic pterodactyls nude by Professor H. G. Seeley in the Cambridge greensand have lately been ■described in these columns. Since these were made, Professor 0. C. Marsh, of Yale, wa» the first to discover toothless pterodactyls in the clnlk of Kansas, but of thtse- he gave only preliminary notice*. DuriSg the past 10 years these fossil ■vertebrates have been studied in detail by Dr George Eaton, who na» published a memoir on the osteology of pteranodon. Thi* species of flying reptile is the latest. largest, and most specialised. So large ■were they that the span of their wings ranged from 18ft to 22ft. How were these enormous wings supported?, A mass of fused thoracic vertebra were firmly articulated with the scapula, and between this fused mass and the equally rigid satrnm there were only three dorsal vertebne. The tail was short and small, and the wing membranes were partly supported by slender hind limbs. The elongated jaws were toothless. The mandible was rigid and grooved, as in the pelican, and the animal was presumably a fish-eater, with a small pouch below the mandible. The supioorbital crest was enormous, and the large temporal muscles, gave great snapping power to the jaws. —Sexual Selection of Darwin's extensions of his theory of natural selection has been more contested than his doctrine of sexual selection. Though it has met with some support, it encountered the formidable opposition of Wallace, and- the balance of scientific opinion appears to be against it. Yet facts in its favor are constantly being found. Julian Huxley, a grandson of the professor and son of his biographer, has been observing the courtship ol a common British birl, the red shanks. Wallace maintained that, after a battle between, the cock birds, the hen tamely accepted the victor. That does not coincide with Mr Huxley's observations. According to these, there was no rival simultaneous display among several males; in each case a single hen was courted by a tingle cock. In quite 90 per cent, of cases the hen rejected the advances of the male, during either the display or the pursuit, by simply flying away. Sexual selection bv the female was thus a reality. Darwin 1 * view seemed thus to be confirmed. In one respect the obsrvations did not meet Darwin's requirements. The plumage was not confined to the male, as in Darwin's cases, but. was common to the two sexes. There was no selection through plumage. The display consisted in the male's directing attention to the underside of the wings by raising_ and vibrating them, fanning out the tail; and exhibiting his red legs by slow and high stepping. Differences of behaviour were therefore the only material for selection, and Mr Huxley infers that no other differences between the sexes originally existed, and all others were in time superadded to these. It is a questionable view, and is right in the teeth of the mest accepted theories. It is generally held that eexual characters, where they differ in the sexes, were first acquired "bv the male, which transmitted them onlv to males; in virtue of the law of the limitation of heredity by sex; next by the female a* well; and then transmitted to both sexes. Evidently Mr Huxlev must extend his observations, and refrain from theorising in advance of his facts. —Crystalline Metals.— When we speak of crystals we usually think of minerals or artificial salts, of ice or frost, and it is the crystalline characters of these that have been chiefly studied. If the crystalline characters of metals have been less considered, it is because they ai'2 rarely to be found in regular and well<kfinesl forms. Yet the older cryaiallorr»phers had seen, and Ruskin has beautifully described, the crystals of certain metals, like the rust of iron and (what he calls) micaceous iron. We now know that masses of metal are entirely crystalline. They ai« found, by peculiar methods, in bismuth, tin, aluminium, and silver, but especially in iron and steel. The crystals of galvanised iron are stated to resemble closely those of frost figures on glass. Crystals of steel are found as long as 15in, and have a characteristic form. The treelike structure of solid masses of crystalline metal is most readily seen in an alloy, and yet it is somewhat inconsistently said that pure metals are more disposed to assume tree-like forms than compounds. In alloys of copper and antimony the minute antimony crv&tals assume a parallel direction. In Swedish pig-iron and in phosphereopper masses are to be seen that possess a duplex structure and have been termed "colonies" by Benedicks, of. Vienna, who has discovered that each "eohgiy" " an intergrowth 6i

two,, constituents. Evidently ojyatallographyis making a fresh sta*t. The new begins -where-the old leaves off. Ihe old concerns itself with norraar crystal* and geometrical crystallisation. The new I studies crystallites. These may be embryonic crystals, or they may be failures of ! crystals that have been " thwarted in their 1 development bv external conditions, says Dr Cecil Desch. They are important because thev are elements in the structure of metals." The chief task of the now science is to investigate the relations between the crystalline structure and the physical and mechanical properties. And the* results of such study maV influence technical practice. The uses ot metals and alloys may be governed by it. , -—Synthetic Rubber.— ! The enormous demand for rubber that has arisen out of so many new inventions, with bicycles and motor cars among them, has stimulated chemists to caual-they carnot surpass—their success with coloring matters and with scents. First artificial lubber was produced. But this was not a success. It consisted of natural rubber mixed with other substances. ' Then it was-ascertained that isoprene, divinyl, and similar compounds could be polymerised and converted into rubber, provided they could be cheaply obtained. The cheap production of isoprene was first experimented upon. Starch was the product finally selected. Out of it Dr Fernbach, of the Pasteur Institute, after 18 months labor, devised a cheap process for producing fusel oil. Isoprene, thus produced, had next to be polvmerised and converted into rubber. Then Dr Matthews and the staff of chemists employed by Messrs Strange and Graham threw themselves on the problem. Many experiments were made, and various substances were used. Pei-kiii, Ramsay, and Fernbach co-oper-ated, but with indefinite results. Accident (a .prepared accident) solved the problem. Raring left some metallic sodium in contact with isoprene for two months, Dr Matthews " found that the isoprene had turned into a solid mass of rubber." And sodium was seen to be "a general polymerising agent for this class of material." The discovery was independently made three months 'later by a German professor, Karl Hen-res. —Fish Measurements.—

Professors Petersen and Meincke have lately founded a new branch of science, connected with the measurement of fishes. A few results may be noted. A general belief is'confirmed'by it's being found that male fishes are generally smaller somewhat than the females, and also (is not this a new point?) less numerous. Another striking and novel result is that the age and growth of fishes are indicated by their scales. In boreal fished, at all events, the rapid changes that take place in summer, with, the slow changes that take place in winter, are marked iu all the bony structures—vertebrae, gill covers, scales, etc. Visible rings or zones, not unlike those by which "the age of a tree is known, are formed in these structures, and by means of these its summers and winters can be counted. This was first discovered by Hoffbauer in respect of the carp's scales in 1899; next by Reibiseh, of the plaice; by Stuart Thomson, of the scales of gadoids ; while Heincke and others have shown bones to be good indices of growths. Five others—Da-mas, Sund, Brocb, Dahl, and Lea—have studied the age of the sprat, cod. herring, salmon, ana trout by thqse methods. —Other Results.—

These investigations have shown that the growth of fishes depends largely on the temperature. They further show that the shape of the fish depends on the history of its growth. As a natural consequence there is found an almost infinite variety of types of growth. Growth varies greatly, according to the surroundings. A key is at the same .time afforded to the migrations of fishes. Other results have been ascertained. The age at which maturity occurs, the duration of life, and the variations'in the age-composition and magnitude of the fish stock can now, or will soon, be determined. Problems relating to the distribution are also in the way of being solved. A great advance in our knowledge of fishes may confidently bo looked fonvard to in the near future.