SCIENTIFIC.

Otago Witness, Issue 1934, 19 March 1891, Page 32

SCIENTIFIC.

— The Italian astronomer Schiaparelli, ! who recently discovered the fact that Merj cury performs only one rotation on its axis during its entire revolution around the sun, and who has made more discoveries in our planetary system within a few years than all other astronomers put together, has just announced another important discovery. He now asserts that Venus, the brightest of all the planets (the twin sister of the earth;, also turns but once on its axis in the course of a revolution around the sun. In other words, there is no alteration of day and night on Venus, as on the earth. The planet enjoys perpetual day on one side of its globe, while the other side is plunged in unending night, just as is the case with our moon. Astronomers have heretofore believed that the time of Venus' axial rotation corresponded almost exactly with that of the earth's. This was supposed to have been established by noting the return of spots visible on Venus to a similar position night after night, but Schiaparelli shows that these observations have probably been misinterpreted, and that instead of indicating a rotation period of 24 hours, they rather confirm his conclusion that the rotation is performed in 224-7 days, which is the time the planet takes to complete a revolution around the sun. Schiaparelli says the axis of rotation of Venus is nearly perpendicular to the plane of the orbit. If that is so, Venus has no diversity of seasons, such as the earth enjoys. Its equator for ever burns with the heat of an unending summer, and its polar regions undergo no change of temperature. The equatorial heat on Venus is vastly greater than that on the earth from the fact that her distance 'from the sun is only twothirds that of the earth. Moreover, the fact that her heat is unbroken by the alternations of night and day must still more greatly intensify the temperature of the sunny side of that planet. The cold of the opposite side must also, for the same reasons, be greatly intensified. There may, however, be some modification of the direct and continuous heat of the sun on Venus. All telescopic observations of the planet testify to the blinding brilliancy of its surface, and the j most reasonable hypothesis yet put forth to account for this phenomenon is the existence of an extraordinary amount of cloud in its atmosphere. Anybody who has watched a sun-illumined cloud knows how splendidly it reflects the light, and, of course, in looking at the clouds of another planet we can practically see only the sunny side. If, then, as appearances indicate, Venus' atmosphere is largely filled with clouds, the effect would be to screen off the superabundant sunshine, and perhaps render even perpetual daylight far less obnoxious than we might at first sight be disposed to regard it. There are reasons for thinking that the atmosphere of Venus is most abundant. Its depth has been calculated to exceed that of the earth by about one-third, although Venus is a slightly smaller planet than ours. The existence of watery vapour in this atmosphere has been clearly established by spectroscopic examinations. Of the extent or even the existence of oceans on Venus we know nothing by direct observation, but since the planet possesses an atmosphere and clouds, it is not unreasonable to conclude that it must have oceans capable of supplying the needed vapour. — Professor Boys, who has shown sudh a high degree of experimental skill in the preparation of fine quartz fibres for scientific instruments, has succeeded in making tubes of quartz possessing the most valuable properties. They stand an enormously high temperature. At a heat which makes platinum as fluid as watqr they are still solid, and it is impossible to crack them by sudden heating. The tubes, like glass, are transparent, and far less corroded by certain chemicals than glass is. Such tubes will be a great boon at once to many chemical and physical experimenters ; but one is tempted to wonder how long it will be before it is possible to manipulate this grand form of glass abounding everywhere so that it will be available for everyday use. One thing is certain— that before long quartz will be extensively used for insulating chemical electrical conductors, as it allows marvellously little leakage of electrical current to take place through it, and first-class cheap insulators are one of the indispensables for the higher applications of electricity which are yet to come. Such are the same strange ramifications of soientifio research that an investigation begun for the preparation of i a simple thread in a scientific instrument immediately shows bearings on the future of I electrical engineering. — In Cumberland, north of the Duddon estuary, there has been worked for the past 20 years a valuable mine of hematite iron, a form of ore which is of particular value for admixture with certain kinds of steel. The mine has been worked as close to the sea as was practicable without running a risk of flooding the workings; and the proprietors were at length induoed to seek a fresh concession from the landowner, to enable them to win the ore from underneath the sea-bed. This necessitated the building of a vast wall or barrier to keep the sea at bay, and this difficult undertaking has just been successfully completed. The wall is two-thirds of a mile in length, and is 50ft high from foundation to parapet. As it is exposed to the full fury of south-westerly gales and Atlantic rollers, the work has had to be carried out in a very solid and substantial manner. It ia hoped, that its erection will permit the working of the mine for 25 years, a matter of great importance to the district, seeing that 1500 men find employment there. —What may prove to be the origin of a new class of musical instrument has resulted from a study of tilie musical qualities of telephone plates. If a telephone plale is kept vibrating by au electro-magnet, it gives oat a musical note whose pitoh oan be regulated by moving a point firmly against it as a violinist moves his fingers along the string, the pitch prising at the point is taken towards the oentre. Now, the telephone plate does not give a very pure note of its own, but the idea of using it in this manner, if worked out with proper acoustic aids, may easily lead to a new and useful class of musical instruments, possessing the grand power of the human voice and the violin, of taking any musical interval whatever within its compass. '