SCIENCE SIFTINGS.

Auckland Star, Volume XXXVII, Issue 197, 18 August 1906, Page 10

SCIENCE SIFTINGS.

V SMALLEST ELECTRIC MOTOR.; What is- claimed to be .the smallest electric motor in the world is in thepossession of a Texas electrician and watchmaker, who made it as "a scarf pin. According to. the. "American Mechanic," it weighs I pennyweight and 3 grains, and is'run by, current .from a small silver chloride battery. The ;lield magnets arc made .from'two very fine pieces of sheet iron scraped down and polished. Instead of copper as a conductor, gold is used. The magnets - are held together I>y ■■' gold screw's, and wound with very fine silkcovered wire, and the commutator bars ate of gold* '...--, THE ANIMAL THAT CAUSES COLDS. The common cold is now classed by some authorities among the diseases due to germs. Just what germ is the cause has not been settled, but it seems that more than one species may take an active part, and* a recent investigator reports that in One severe local epidemic he found "micrococus catarrhalis" present in all cases, while in two other epidemics, both of a severely infectious character, the germ was recognised in every Case examined at its onset. The organism, however, "often disappears within 24 or 4S hours. In the second and third epidemics re-infection sometimes occurred, producing either a second acute cold or else a chronic cold lasting for months, and the germ was so virulent that it lolled inoculated mice, guinea-pigs, and even rabbits. AUTOMATIC PIANO-PLAYERS AND INDIGESTION. The automatic piano-player has come to stay, of that we may be sure, and we welcome the fact, for it brings most charming music into many homes ! that would otherwise lack its. refining influence..But (says "Science Sittings") - there is a health aspect of automatic piano-playing that must not be overlooked. Excessive pedalling with, the feet after a full meal is likely to lead to torpor and indigestion. The blood flies to those parts of the body where the demand ' for its services is most exacting; and if, after the evening meal, say, in order to pedal the piano-player, we induce the blood to go to cur legs, it obviously must detract from its labours in the cause,of digestion elsewhere in the body. In fact, we have traced cases of to this cause, but the remedy is simple; after dinner rest awhile before playing. WHAT HEAT IS DEADLY* There are many factors to take, into consideration in answering the question as to what heat is deadly. Persons can stand a very high temperature :for a short time- A temperature applied externally to the limbs for th? cure of rheumatism can be raised, Dr". Max D. Slimmer informs us, considerably above the boiling point of water without injuring the patient. This is undoubtedly due to the protective action of the perspiration. If a person has plenty of water to drink, he can accustom himself to very high temperatures. The workers in iron and steel mills work in temperatures'so high that'if they wear glasses the hot metal of the frames has been known to burn their faces. Of course, one must become accustomed to such excessive temperatures, and they are always very exhausting. EXTERMINATING EATS ON SHIPS. The British Local Government Board has published a further report on the destruction of rats and disinfection on shipboard with sulphur dioxide, by Dr. John Wade. It is found that rats and insects are destroyed in less than two hours by air containing 0.5 per cent of sulphur dioxide, a condition easily realised in cabins, empty holds,, spaces round cargo, etc, but for adequate penetration of closely packed cargo, air containing 3 per cent of the gas must be circulated around the cargo for. eight to 12 hours. Non-sporing pathogenic bacteria are also killed by this treatment. Textile fibres and fabrics, metal and furniture, are not affected by sulphur dioxide, but are liable to injury by the accompanying sulphuric acid when the gas is generated by burning sulphur, unless, ihey are protected. Meat, fruit, vegetables, and wheat in bags are deleteriously affected. Liquid sulphur dioxide may be employed as a source of the gas, but burning sulphur, as in the Clayton process, is on the whole preferable on the ground both of convenience and of economy. THE EARTH MUST BECOME OLD. Newton surmised, although he could give no reason for it, that the earth would lose all its water and become perfectly dry. Since then it has been found that Newton was correct- As the earth keeps cooling, it will become porous, and great cavities will be formed in the interior, which will take in the watsr. It is estimated that this process is now in progress, so far that the water diminishes at the rate of the thickness of a sheet of paper each year. At this .-rate, in 0,000,000 years the water will have disappeared from the surface of the globe. The nitrogen and oxygen in the atmosphere are also diminishing all the time., It is in an inappreciable degree, but the time will come when the air will be so thin that no creature we know could breathe it and live; the time will come when the world cannot support' life. That will be the period of old age, and then will come death. »