SCIENCE NOTES.

Otago Witness, Issue 3205, 18 August 1915, Page 73

SCIENCE NOTES.

Pine Needles in Winter. — In the American Journal of Botany Mr John H. Ehiers describes the results of measurements of the internal temperature of pine leaves in winter, obtained by means of ingenious thermo-electric apparatus. He found that these leaves, under winter conditions, maintain temperatures from 2deg to lodeg_ Centigrade higher than the surrounding air, owing to the absorption of radiant energy. The average of 650 readings taken in February between the hours of 8 a.ra. and 3 p.m. was a little more than 3dog above the air temperature. This difference, says the author, is sufficient to be considered an important factor in photosynthesis. -—Lightning Conductor Containing Radium.— Mention is made in a recent number of the German journal Prometheus of a lightning conductor, which, it is claimed, g>ves much more effective protection than the usual rod. The inventor took an ordinary lightning rod and equipped it below the point with a disc that was overlaid by electrolysis with about two milligrammes of bromide of radium, so put on that it was weatherproof. The experiments made showed that the preparation of radium ionised the air, making it conductive for a wide circuit around the point of the lightning rod. This led, naturally, to a decided fall of potential in the atmospheric electricity and to equalisation betrveen the various strata of air lying in layers one over another. The change of atmospheric electricity in these strata flowed towards the point through the air, which was still a good conductor even at a considerable distance from the point of the conducting rod, and was carried from the point to the ground. In addition to the increase of radius of action of the lightning rod, the ionising of the air by a preparation of radium seems to cause the carrying off of stronger currents of atmospheric electricity. The Now “Poison” Gas. — The report from France that the Germans are substituting another poisonous gas tor chlorine is not surprising; but the suggestion implied by the letter of a French soldier that this now gas is formol should be carefully examined. If it is correct that chlorine is being replaced by another gas it would be a fact of no small military importance. It would suggest that the Germans, having discovered the effects of the chlorine fumes and the precise nature of the chomically-treatcd respirators, were endeavouring to render our protective measures useless by employing gases which would not lose their effectiveness in contact with certain chemical substances. It is highly improbable, however, that formol is the new gas. To begin with, its fumes arc lighter than air, and would be rapidly dissipated by the slightest breeze. Further, notwithstanding that formol is a powerful germicide, it is only slightly poisonous to human beings, although the fumes are intensely irritating. What is quite possible and even probable is that the Germans arc using formol in colossal quantities for disinfecting the trenches and for antiseptic purposes generally, and that under some peculiarly favourable circumstances the fumes have been carried to the French trenches. Home-made Chemical Fire Extinguishers.— A notice just issued by the Metropolitan Commissioner of Police emphasises the desirability of householders being provided with a means of extinguishing fires in the event of an air raid. There are on the market many admirable forms of chemical fire extinguishers, but those who, for one reason or another, are not furnished with any of these could in case of emergency improvise a suitable extinguisher by means of readily procurable chemical substances. One method would be to dissolve 201 b of common salt and 101 b of ammonia chloride in six and a-half gallons of t water. This could either be used by throwing bucketfuls of the solution on to the fire, or the solution could be put into large bottles, made of thin glass, which could be thrown on to the fire with sufficient force to break the bottles. Another method would be to mix together 81b of washing soda, 41b of alum, 31b of borax, lib of potassium carbonate, and 241 b of waterglass solution, and add IJJb of the mixture to a gallon of water when required for use. Still another formula is calcium chloride three parts, common salt one part, and water 20 parts. Failing anything else, syphons of soda water are useful appliances in small fires, since the water is saturated with carbonic acid gas. Obviously, however, this method should not be relied on. as it would bo useless in case of serious fires. Carriers of Disease.— Dr Louis Sambon, the famous expert on parasites and epidemic disease, who was among the first to indict the fly in the early eighties, is taking a loading part in a great national campaign against the various insect carriers of disease —of which flics, of course, are only one—now being organised by the National League of Physical Education. The danger of serious outbreaks of epidemics owing to infection being conveyed by insects from the battlefield is causing much anxiety to the authorities, and the idea of the league, which, has boon in consultation with many experts and medical authorities or. the subject, is to invoke the powerful aid of the housewife in waging war against the insects believed to bo chiefly responsible. Many leading -women are associating themselves with the campaign, for the formal opening of which the Lord Mayor has lent the Mansion House on July 5; but as the menace to health is so grave and no time should bo lost, Dr Sambon, who is lecturer to the London School of Tropical Medicine, has already made a start by impressing unon London women teachers that fleas, bugs, and lice are responsible for more diseases than the public generally imagine, while the rat and mouse arc also important as carriers of insects which convey the diseases. Ccre-bro-spinal meningitis, popularly known as spotted fever, is. he savs, possibly an insectborne disease, although this lias not been proved. Diseases certainly bred by insects include typhus bv lice and the common bug, enteric fever and cholera by flies, plague by fleas and the common bug, and relapsing fever by lice*