SCIENCE NOTES.

Otago Witness, Issue 2253, 6 May 1897, Page 48

SCIENCE NOTES.

• . • Before the British Association for the Advancement of Science, at the Liverpool meeting, Professor W. Rid g way read a paper on " The Starting Point ot the Iron Age in Europe." He said that the origin of the iron age is one of the most important points in European arc! re:>logy. Scandinavia could not be its place of origin, for there the iron age began later than the Qbristian era. And it is admitted that the iron age came in per saltum in the Swiss lake dwsllings, in Italy, Greece, France, and Britain. Hellstadt, in Austria, was, in fact, the only place in 'Europe where articles of iron were found gradually replacing those of the same kind in bronze. Near the Hellstadt cemetery lay one of the most famous iron mines of antiquity. It was from this Austrian centre that the use of iron spread into Italy, Switzerland, Gaul, Spain, Greece, and eastern Germany, among tribes that were using bronze weapons and implements, and .Tacitus was our authority on this point. In a discussion Dr Montelius pointed out that there were instances of the use of iron in Scandinavia, gradually superseding bronza, in the fifth or sixth century B.C. A. J. Evans said there is very early evidence of the use of iron in Syria, whence it spread to Greece, aad the spread of iron in Britain was earlier than is generally supposed — as early, Jn fact, as the sixth century 8.C., especially In Ireland.

• . • What is called "pole"' paper is paper saturated with a substance that is sensitive to the action of the electric current, and that permits of instantly distinguishing the positive from the negative pole in an epsn circuit. According to the Annales de Ohimie Analytique this paper is prepared as follows : — Ecom one to two grammes of phtalsin of phenol are dissolved in 10 cubic centimetres i>f SOdeg alcohol. The solution is poured Into a glass vesoel and a^sut 110 cubic centi-

metres of distilled water are added to it The result is a milky emulsion of phtalein. On another hand, 20 grammes of sulphate of soda are dissolved in about 100 cubic centimetres of distilled water. The first solution is poured into a porcelain tray, and several sheets of slightly porous paper are dipped into it one after another. These sheets, after being allowed to drain, are immersed, while still damp, in the soda solution. The paper, after being dried, is extremely sensitive to the action of the electric current. In order to ascertain the direction of a current a piece of the paper is dampened, and the extremities of the two copper conductors are applied to it in such a way as to leave a space of about half an inch or an inch between them. One of tb.9 wires instantly produces upon the paper a deep red line, which is due to the action of the soda set at liberty, and which extends toward the negative pole upon the phtalein. The other wire remains inactive.

• . • An enormous amount of electricity is generated and passes into the air from spray. Even small cataracts only a few feet high, provided they bring down a large amount of rapidly dashing, spattering water, produce large charges. The chief cause of electrification seems to be the tearing asunder of the drops as they fall on the wet rock surfaces at the bottom of the fall. It has been lately shown that air, even absolutely dust free, can be electrified by a jet of water. A noted scientist says :— " The supply of 'electricity in the air is constantly renewed. The waterfalls in the valleys, the beating of little wave 3on the shores of lakes and rivers, the splash of raindrops on the ground, send masses of negative electricity into the air. On the other side, the waves of the sea, as they break against the rocks and fall back in millions of droplets upon the beach, supply the air with quantities of positive electricity, the amount of which rapidly increases after each storm.

••• Few medical. men who have bad considerable opportunities of studying: inflaenza in its remoter as well as in its more immediate seque'se will be surprised to read the verdict given by Dr T. S. Olouston, medical superintendent of the Royal Edinburgh Asylnm for the Insane, concerning the abiding and serious effects of that strange disease upon the nervous system. " Probably no snch destroyer of nervous energy," says Dr Olouston, "and no puch producer of nervous disease, as the influerz* poison has appeared in the world in recent times." To him, as a specialist in nervous disorders, it is " the most striking medical fact of his time." Mania and melancholia, undue exaltation and undue depression, are two types of mental disease which stand to each other in the relation of direct contrast. Under certain seta of conditions mania will be the predominating type ; xinder certain other sets, melancholia. Conditions which profoundly depress the nervous system culminate in the melancholic type of insanity. All this is familiar, not to the alienist only, but to the general practitioner of experience. Certain facts, to which Dr Olouston gives prominence, bring out in a very striking way the profoundly depressing effects of influenza upon the nervous system — effects which continue for years, and may only cease with life. In the seven years beginning with 1883, and ending with 1890, the cases of mania at the Morningeide Asylum far outnumbered those of melancholia. On an average there were 45 more cases in each year. That is a common experience at lunatic asylums. Bub during the seven years period just closed — that is, 1890 97 — the average of mania cases has only been 18 more than that of melancholia. The most striking fact of all which Dr Clouston publishes is this : that in the three years 1890 91-92, the years of the greatest prevalence of inflaenza,. the cases of melancholia actually outnumbered those of mania, and that during the whole of the three years. To influenza, and to influenza alone, Dr

Clouston attributes these striking variations in the usual circumstances of the history of insanity. — The Hospital.

• , ' Of the numerous new substances made known by chemists early in the present century, Dr T. L. Phipson says, in Knowledge, by far the most unpromising of possible usefulness was the metal thorium and its oxide thoria. Bsrzelius, the discoverer, succeeded wiih difficulty in extracting a minute quantity of the metal in powder from the Norwegian rocks. Aside from burning at a red heat with greater brilliancy than even magnesium, thorium seemed to have no striking properties, and its oxide resembled common lime, but the light-giving property is just brirgirg thi3 rare metal from tha complete oblivion in which it has lain for 70 years. Of all the metallic oxides that have been tried for the " hoods " or " mantles " of incandescent turners, which are making street gaa a rival of the more expensive electric light, none has proven equal to thoria. The consequence is a brisk demand for this substance, so long believed to be useless, and at various timts during the last two or three years a pound weight of thoria has been freely sold at from £44 to £50. The minerals thorite, orangite, and pyrochlore, which contain a large amount of thoria, are still very rare. A more promising source of supply is monazite, wbioh con-tains-18 per cent, of thoria, and forms Ito 7 or 8 per cent, of the so-called monezlte sands that have been recently found in some quantity in North Carolina, Brazil, and Quebec. Several hundred tons of the sand are now shipped yearly from Brazil to Er gland or Hamburg, while a ton of the Norway thorite and orangite supplies £7000 of thoria in the same time.

• . • la the New York Medical Journal Dr Alexander M'Ocy publishes a series of cases illustrating the irruption of the teeth into the nasal cavities. This painful and fortunately rare condition, he observes, is attributable, as a rale, either to abnormal development with rotation of the dental germ — the enamel growjng upward instead of downward — or to extrafollicular development. A case originating in traumatic displacement of the normally irrupted tooth is also recorded. As a rul<«, the floor of the nasal passage is the seat of the invasion the enamelled crown presenting, though extrafollicular irruption at a higher point i<? also recorded. As might be expected, the offender is usually a front tooth, incisor or canine, but others as far back as the wisdom teeth have been found thus displaced. The clinical interest attaching to cases of this kind is largely that of secondary disturbances, which comprise local necrosis, with suppuration consequent on the boring action of a hard body travelling through previously formed bone, otitis, and even laryngeal spasm. The journey performed by such erratic teeth is sometimes neither short nor rapid. In one case, as read by the light of symptoms, a wisdom tooth appears to have made its way duiißg a period of 30 years through the alveolus into the antrum of Highmore, and thence by ulcerative inflammation through the lateral nasal wall and inferior tnrbinated bone on to the nasal floor, whence it was ejected.