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Otago Witness, Issue 2318, 4 August 1898, Page 48

SCIENCE NOTES.

— " A modern gunner," says on official in the United States army in a recent article, " must be able while shells are bursting above his head and his comrades are falling around hire to work out a problem like this : ' That ship is three miles off; she is approaching at such and such an angle, her speed is 15 miles an hour, the forward turret is the place to "hit, the wind is strong from 9 o'clock, the temperature is 75 and the barometer is 30.06, I must therefore give so many degree? of elevation and allow so many points for windage." Having done this he must aim his gun with the greatest rapidity and exactness and fire. If he makes a mistake in any of the factors of his equation, or lays the gun so that the variation of the sight is greater than a fifteenth of an inch, his shot is wasted. If he is right in everything he may disable tin 3 ship he is firing at, and by so doing save the city he is protecting." A single load for a 13-inch gun costs about 1250d01.

— Recent researches have gone far to render possible the assertion of Nordenskjokl and others that a large portion of the earth's constituents may be of cosmic origin — that, in other words, in the course of ages the distant stars and other heavenly bodies may have contributed of their substance to thicken the crust of our world. For example, at various times and in various places there has been collected from the snow a black powder containing metallic iron, and in some instances cobalt and nickel, while on the " inland " ice which covers Greenland a peculiar mineral powder, named kryokonite, mixed with grains of metallic iron, has been detected. This dust consists of small, angular, double - refracting crystal fragment*, without any mixture of particles of glass, and is therefore verj- different from the glassdust that is commonly ejected from volcanoes. From these and similar data Nordenskjold ventures on the assertion that not improbably, if this dust falls in an equal amount all over the globe — and though the snow enables it to be detected more easily than on earth there is no reason for supposing that it does not — something like half a million tons drop from the celestial spaces hi the course of a year. The shooting stars must discharge an immense quantity of these luminous particles. For hours at a time wo

sec them falling ; and when we remember lhac this has been going on during unnumbered geological ages it is not impossible to regard it as an important factor in the history of our planet. In brief, it may be found " that a considerable quantity of the constituents of our sedemcntaiy strata, especially of those that have been deposited in the open sea far from land, are of cosmic origin, and will throw an unexpected light on the origin of the fire-hearths of the. volcanoes, and afford a simple explanation of the remarkable resemblance which unmistakably exists between plutonic rocks and meteoric stones — namely, by showing that the principal material of the plutonic and volcanic rocks is of cosmic origin, and that the phenomena of heat which occur in these layers depend on chemical changes to which the cosmic sediment, after 'being covered by thick terrestrial formations, is subjected." " Without quite homologating this idea, it is certain that meteoric, or native, iron is — and has from the remotest ages been — falling on the earth's surface from the immeasurably distant regions outside of our atmosphere. — Our Earth and its Story. — The Government artesian well at Lower Brule agency is certainly a freak of its kind, says "The Omaha Bee."' Originally the pressure threw a solid 6in stream of wa'tei to a height of 21 fl above the top of {he wellcasing. Subsequently the pipe became temporarily choked up, and at such timed the water would not flow at all foi periods of two or three days. Then, without apparent cause the pipe would suddenly become clear, and the water would again spout to the height of 21ft. After continuing for a few days, during which time it almost constantly 'spouted laige quantities of sand, it would onco snore become clinked and cease to flow. This became so frequent and regular that in time the agency employees became accus<om°d to it. and paid no particular attention to the freakiness of the well, winch is constantly under their observation. But now the matter has taken another and more peculiar turn. Arrivals from the agency report that, commencing about three weeks ugo, this well has been at intervals forcing out apparently endless quantities of blue clay. This in itself is nothing strange, but the manner in which the clay is carried through the pipe is something out of the ordinary. The blue clay entirely fills the 6in pipe and arises slowly above the top of the casing, exactly as sausages emerge from a sausage machine, until the top is so high in the air that it becomes overbalanced, when five oi six feet topples over upon the ground. The con-

tinued upward movement of the clay in a few minutes causes more of the column to topple over. This has continued until circular pieces of the blue clay aggregating several hundred feet in length have been deposited on the ground adjacent to the well, necessitating the employment of men to remove the huge deposits before the top of the casing becomes completely buried. The discharges of blue clay are accompanied by very little water, and the clay, probably from the great pressure required to force it through the well casing, is always as dry and hard as a brick. Another peculiarity is that these eruptions invariably commence a short time prior to the advent of windy or stormy weather, and continue until the weather again becomes settled.

— So-called " dark days," of which a number of remarkable ones have been recorded in the earth's history, have usually been explained by the presence of thick smoke due to great iorest tires, accompanied, perhaps, by some peculiar atmospheric conditions. There have always been a few, however, not furnish a complete explanation, ani the observations made on a series of such days that occurred in Siberia in 1836 seem to strengthen the case of these doubters. If we are to believe official reports, the dense smoke that covered half the continent of Asia on those days was due neither to fires nor to volcanic eruptions. It is the opinion of M. Adam Rzyszczewski , who describes the phenomenon in the Bulletin de la Societe Astronomique, Paris, that the earth at that time was passing through what he calls a great cosmic cloud — perhaps a gaseous nebula. The only tn üble is that in this case it would seem that the whole earth ought to have been equally plunged in the smoky substance, but he ingeniously explains the fact that it was not.

— Talc is extracted on a large scale from the granite mountain oi St. Birthelemy, in the French Department of Arriege, about 20 miles from the main chain of the Pyrenees. The principal quarry at Tremouin is worked in three banks or terraces, each about 49ft high. The best rock is of a bright white tint, and feels greasy to the touch when reduced to powder. The quarried rock is brought by a tramway to the end of the quarry in the Axiat Valley, and then by waggons 11 miles to Lusenac, where water power is taken from the Arriege River. The mechanical preparation consists of drying in a rotary oven, breaking up small, grinding and sifting, the grinding being effected in mills with steel balls. The larger portion of the product is converted into powder, only a small portion being sent away in a rough state, or cut into pencils for writing on metals. Besides its use in soap and paper making, talc enters'lnto the composition of axle grease, while it also serves as an insuktor of the greatest value in the construction of electrical instrument.

— Unslaked lime is best suited for the prevention of mould. It is blown, in the shape of a fine powder, on the walls of the cellar aial into the joints and crevices by means of the bellows, or else thrown on with the hand. The walls have to bo damp ; dry walls have to be well moistened previously. Tho lime slakes with the adhering water and kills all organisms. On the day following the walk are washed, and, as experience has pio^ed, the cellar will remain free from mould for at least two yeais.- Scientific American.

— It is stated that the setting of pla.stcr of Paris is very much accelerated if the plaster is mixed with a 5 per cent, solution of common salt — which may be roughly made by adding a tables-spoonful of salt to a pint of water.

— Ordinary food is not liable to get ptomaines where proper care is taken of it. Where food is frozen, thawed out, and frozen again, it is very dangerous. Cold storage is responsible for many ptomaines. We eat chickens that have been kept in cold storage a year, and put there without having had the intestines removed at that. Think of it ! These are hung up in the market. We buy them and eat them, and nature eliminates the poisons that they convey to the human system. This is one of the dreadful penalties of civilisation and the concentration in large cities that makes such a thing possible. There is very little harm in hung meats in cold weather, for the micro- organisms that get in their work in cold weather are not very dangerous. Fish is very apt to decompose rapidly, more rapidly than ordinary flesh, and putrefaction is indicated by a stale, tainted taste that is apt to make one ill, but does not kill. Oysters, unless perfectly fresh, are very poisonous, and when oy&ters look glazed, have a coat of mucus over them, (he person who is about to eat them may be sure th-il putrefaction has set in, though it may not -set be perceptible to the taste. — Dr George Shrady, in the New York Sun.