SCIENCE NOTES.

Otago Witness, Issue 3211, 29 September 1915, Page 79

SCIENCE NOTES.

Automatic Tyre-pump.— A tyre pump that not only pumps up any tyre within a few minutes, but that keeps the tyre at that pressure regardless of punctures, is a British invention. The pump can be attached to the hub of ,the wheel in less than a minute by any person. It works on the rotary pump principle, each revolution of the wheel, while running the car, driving air into the tyro; and so effective has this device shown itself during a recent official tost by the Royal Automobile Club of Great Britain that a tyre, deliberately punctured in five places, was kept at full pressure as long as the car was kept running. The device appears to have solved the roadside repair problem. No car need stop because of a puncture if fitted with one of these pumps, as it can be run with case and without danger to the nearest garage or repair shop. The Atmosphere'of Mars. — In a recent number ’ of the American Museum Journal Dr Percival Lowell reviews the spectroscopic evidence in regard to the subject above-mentioned, and presents a well-reproduced spectrogram of Mars, with two of the moons for comparison. A marked difference is seen in the absorption band of water vapour in the Martian and lunar spectra respectively. In the case of the waterless moon, the absorption occurs only in the earth’s atmosphere, while in the case of Mars the greater intensity of the absorption band points to absorption in the Martian atmosphere as well. Recent spectrograms obtained by Slipher actually si|6w something as to the horizontal distribution of water vapour in the Martian atmosphere. The polar snow-cap was in Erocess of melting, greatly increasing the umidity of the air in that region of the planet. Similar comparisons of lunar and Martian spectra prove, according to Professor Very, the presence of oxygon in the atmosphere of Mars, about half as much as in the earth’s atmosphere. How Insects Smell.— The scat of smell in insects has been singularly elusive, and in the prolonged and unsystematic search for it, as shown by the report of Dr N. E. MTndoe, it has been referred to at least a dozen different parts of the body. The recent tendency has been to regard the antennae as olfactory organs. Various structures on these have been chosen by different entomologists; hutdifficulties have been found in the fact that these structures arc shut in by chitinous cuticle, and that they are absent in some insects. Spiders, in fact, have no antennae at all, though they can smell. His experiments have convinced Dr MTndoe that the sense of smell cannot possibly be located in the antennae of ants, bees, and wasps, though this may not be true of all insects, and ho traces the sense to the vesicles or pores discovered by Hicks more than half a century ago on the wings and the legs. Each pore has the form of an inverted flask, with a nerve-ending exposed to the air. When the pores arc covered with vaseline reaction to odours is retarded, and the responses are quickest in insects having the greatest "number of pores. .For example, a drone hive bee, with 2600 pores, responds in 2.9 sec, while a queen, with 1600 pores, takes 4.9 sec. —Crops Injured by Lightning.— While everybody is familiar with the damage done by lightning to trees, little attention has heretofore been paid to the effects of lightning-stroke upon herbaceous plants. A recent paper by Messrs L. R. Jones and W. W. Gilbert reveals the fact that lightning injury is rather common in certain crops, especially cotton and potatoes. Grass, small grains, and maize seem less liable to such damage. The lightning damage to cotton and potatoes frequently extends over roundish spots, one to three rods in diameter, or groups of smaller spots. Although there may be no disturbance of the soil or visible rupture of the plant tissues, the plants near the centre of the spot wilt, blacken, and die promptly, while those near the margin may live days or weeks. The injury for the most part appears first , and worst below ground. All these facts seem to show that, after a period of dry weather, the lightning discharge occurring in a thunder shower spreads horizontally over the moist surface layer of soil. The different liability of different species appears to depend upon difference in tissue resistance or different distribution of the aerial or root systems of the plant within the zone of the discharge. —Rain from a Clear Sky.— In English dictionaries we find the word “serein” defined as a fine rain which sometimes falls from a clear sky shortly after sunset. The word is French, but has become the international designation in meteorological works for this alleged phenomenon. which is always described as quite rare. Has the phenomenon a real existence? The fact that a stereotyped description of it has been passed on from one meteorological writer to another since the latter part of the eighteenth century is by no means conclusive evidence on this point, for science has perpetuated many myths by the process of reiteration. Professor Gustav Hellmann, in a recent publication of the Prussian Meteorological Institute, sees in the conception of the “serein” merely the survival of the old-fashioned belief that evening dew falls from the (clear) sky, and ho finds that the “serein” of early French writers was identical with that “evening dampness ” which was supposed to be injurious to human health. It still remains possible that rain may sometimes fall from a clear sky, though this is not likely to bo a phenomenon peculiar to the early evening. Some cases can bo explained as

duo to the oblique falling of raindrop*, carried horizontally by the wind, when tha clouds from which they came have passec away. —A New Antiseptic.— The long-sought-for ideal antiseptic* which would destroy septic agents in wounds without damaging tissues, would appear to have boon discovered by Dr Alexis Carrel!, of the Rockefeller Institute, assisted by Mr Henry Daken, the chemist, as the result of a series of experiment* conducted at the Military Hospital at Compeigno under the direction of Dr Garrell; and, curiously enough, a group of Edinburgh pathologists, headed by Professor Lorrain Smith, have made exactly the sama discovery simultaneously. The discovery was the subject of a paper read by a professor before the Paris Academic dos Sciences recently. He explained thafe the most powerful antiseptic known to science was hypochioride of lime, but that this_ had up till now been of no practical utility, account of the difficulty in nreserving it, and because of its acidity, which was injurious to the human tissues. Dr Carroll had surmounted these two difficulties by adding boric acid as a preservative and carbonate of lime to counteract the acidity. The now preparation, said the professor had been applied to the most frightful wounds, with the result that within eight days their aspect had been modified in a way quite unknown under the old antiseptic processes. Cases of gangrene had been radically prevented at the very outset. _ Indeed, if the now antiseptic was applied in_ time, it was not too much to say that the infection of wounds might henceforward be considered impossible. —Two Hundred Thousand Bullets per Hour.— A new machine for automatically casting rods of metal in one operation has been perfected in America. At present this, apparatus is of more than usual interest, for the simple reason that by a recent improvement it is now possible to east rods of lead and soft alloys in bars iin and upward? in diameter. The casting of such rods enables the production of bullets for shrapnel shell to be expedited and facilitated ta •an enormous extent, inasmuch as the pre< paration of the rod constitutes ti". firsf stage in the bullet-making process. B< means of this machine sufficient lead rod can be cast to enable 200,000 ballets to bo produced per hour. The process is not only rapid and automatic, but it has the advantage of being very cheap. The electrio motor for driving the machine need) only be of two or three horse-power,- while only one workman i& required. It is stated by the inventor that the operating cost in America is about Is per ton of molten metal poured into the form of rods. _ The outstanding feature of the system is the direct transference of the hot liquid meta.! from the melting-crucibles into the machine during the passage through which solidification takes place, the rod issuing from tile opposite end in a continuous length of solid homogeneous form so long as molten metal is being poured into the machine.