NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XXXIV, Issue 10425, 24 April 1897, Page 4 (Supplement)

NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

CLARIFYING BEER. According to a German authority, turbid beer can be clarified by electric light. It is said that if electric lamps are suspended in the fermenting vessels the yeasty matters are rapidly deposited with the resinous, albuminous, and glutinous substances that are always present. The result is due to the light itself, not to the change in temperature. SUNLIGHT UNDER WATER. "Even where the depth of the sea is 1580 feet, sunlight will penetrate if the water is very clear," says Invention. "Experiments which were made in the Mediterranean Dear

Corsica, 18 miles from the land, prove this to be the case, and the results were shown by means of photographic plates. The depths to which daylight will penetrate depends, of course, upon tho transparency of the water. The Mediterranean is famous for the clearness of its depths, and will admit light to a very great depth. Usually the light of the sun at 150 feet below the water surface is no more powerful thau that of the moon, but at 300 feet it is scarcely equal to the glimmer of twilight, and at 600 feet there is generally perpetual darkness. Tho spotted corals are plainly visible near Mindora in the Indian Ocean at 150 feet

under water. The Caribbean Sea, which is of crystal clearness, shows objects at the bottom at a very great depth."

A SUBMARINE BOAT, " A submarine boat for wrecking and exploring purposes," says the Engineering News, " is about to be built by the Columbian Iron Works, of Baltimore, after the plans of Mr. Simon Lake, a Baltimore inventor. The practicability of the design, it is stated, has been proved by experience upon a small boat. The boat will be capable of rising to the surface and submerging at will, and it may be propelled in any desired direction when on the bottom, A door may be opened, through which the occupants, by donning a diving-suit, may pass from the interior to the outside and back again. The boat will be used principally for searching the bed of the ocean adjacent to coast lines and in locating and recovering sunken vessels and their cargoes. It will he about 54 tons displacement, and will carry a crew of six men. It will be propelled while on the surface by an engine and screw of the ordinary type, and while under water the screw will bo driven by an electric motor, taking current from storage-batteries. A searchlight will light up the pathway of the vessel as she moves along tho bottom."

WOOD I'CLP. Wood pulp is the latest material for tho making of frames for bicycles. The use of wood aftor it has been ground up and reduced to a pulp is not so new as many people suppose. As fur back as 1719 a Frenchman named Reaumur published an essay upon the subject, taking his hint from the wasps, whose paper-like nosts are literally made from wood pulp manufactured by those insects. But it was only something like 30 or 40 years ago that any practical trial of the mutter was made, and

it is almost wholly within the last quarter of a century that the industry has begun to

attract attention and assume importance. For some time past railroad car wheels have been made from wood pulp, and also many other things which aro exposed to great strain in use, and now the attention of bicycle-makers has been attracted to this useful Cincinnati Tribune. INVISIBLE INK. To make invisible inks tako a solution of silver nitrate and distilled water: a single crystal would mako a teaspoonful of solution. Cow's milk will remain invisible till

warmed at a fire—half an hour after writing—but its colour will bo reddish. A solution ot load acetate makes an ink that turns black when held over a gas

jet turned on but not, lighted. Copper bromido makes a colourless solution. When slightly heated the writing becomes visible; it disappears on cooling. A solution composed of loz of sulphuric acid in one pine of soft water also makes an ink that turns black when boated. The juice of a Spanish onion used us ink with a clean quill pen turns brown when heated. Linseed oil, one part; liquor ammonia, twenty parts; water, one hundred parts, mixed and shaken during use, make an ink that becomes visible when dipped in water, and that disappears again on drying. Use quill pens to write with those inks. MOSQUITOES AND MALARIA. An article in a recent issue of the Lancet, from tho pen of Dr. Ainigo Bignoni, brings forward sotno proofs in support of the theory that malaria may be propagated by mosquitoes. If malaria may be propagated by them why may not other ailments to whicii flesh is heir? Flies are said to carry disease, germs from porson to person. But in the case of the mosquito thero is something more than mere carrying, thero is inoculation. And if, as Dr. Bignoni says, in reference to malarial diseases, tho inoculation of hypothesis is admitted, many facts which are difficult to explain by the theory of air conduction find a simple and satisfactory explanation. In the case of malaria, the investigation of the Italian doctor showed that the people of the Roman Oampugna tako vary great care of their mosquito curtain, making it a very close net to exclude all insects. He notes, too, that Emin Pasha never omitted to take a mosquito net with him on his African travels; and to this precaution he attributed his not having had fever, the malarial agent, in his idea, being a corpuscular subStance of which he supposed the close net did not permit the passage. The doctor's inquiries further showed that it had been observed that in the autumn, after the rains, Che mosquitoes increased and likewise the fevers, and that as the season advances they gradually disappear together. He claims to have demonstrated that "malaria behaves itself with regard to man as if the malarial germs were inoculated by mosquitoes." There evidently is more in a mosquito bite than people generally give credit for, and the comfort afforded by a mosquito net is probably not the greatest of its services. EMOTRICITY DIRECT FROM GOAL.

There is no likelihood that much more will be hoard of the direct generation of electricity from carbon, if what Tesla says is to be taken as true. In a recent address ho spoke on the subject as follows "A great deal is expected from a more economical utilisation of the stored energy of the carbon in a battery; but, while the attainment of such a result would be bailed as a great achievement, it would not be much of an advance towards the ultimate and permanent method of obtaining power, as some engineers seem to believe. By reasons both of economy and convenience we are driven to the general adoption of a system of energy supply from central stations; and for such purposes the beauties of the mechanical generation of electricity cannot be exaggerated. The advantages of this generally accepted method are certainly so great that the probability of replacing the engine dynamos by batteries is, in my opinion, a remote one, the more so as the high-pressure steam-engine and gasengine give promise of a considerably more economical thermo-dynamical conversion. Even if we had this day such an economical coal battery, its introduction in centra! stations would by no means be assured, as its nee would entail many inconveniences and drawbacks. Very likely the carbon could not bo burned in its natural form, as in a boiler, but would have to be specially' prepared to secure uniformity in the current generation. There would need to be a great many cells to make up theE.M.F. usually required."- Tosln proceeded to specify a number of other objections to this method of obtaining electrical energy, but the preceding would appear to be sufficient in itself to dampen the hopes of those who have been anticipating the advent of electricity direct from coal.