SCIENCE NOTES.

Otago Witness, Issue 3212, 6 October 1915, Page 81

SCIENCE NOTES.

—Who Invented the Circular Saw? —

Some discussion on this subject has appeared in several British technical publications, and the claim is made that the circular sa’.v was invented and used by a woodturner named Murray at Mansfield, England, about the year 1820. Tho first saw r is described as having been about bin in diameter, and was undoubtedly used on a wood-turning lathe operated by waterpower. James Murray, tho inventor, is said to have been tho son of “Old Joe Murray,” the favourite servant of Lord Byron. —Gas Tubing from Glue.—

Successful attempts have recently been made to manufacture a substitute for rubber tubing out of masses of solidified glue. These tubes, whose trade name is “Sonjatin, ’ are even better than those of rubber for certain purposes, since they are more impervious to gases and more resistant to heat, ft is also claimed that they do not grow rotten so quickly as rubber, and that when encased in a suitable envelope they will withstand high pressure. Moreover, they are very cheap, gas tubes of the new material costing only 60 pfenning per metre. The inventor is Professor J. Traubc. and he states that they are peculiarly suited for conductors of petroleum and gaseoline as well as gases. However, they are attacked by water, which obviously limits their uses.

—Electrocution Trap for Insects.—

A German inventor has devised a very interesting electrocution trap for insects. Upon an insulated frame of either prismatic or globular form two naked metallic conductors are coiled in a spiral with a sufficient space between the windings.- The two conductors are connected with a soui - ce of electricity in such a manner that the current cannot circulate until it is actually used in killing an insect. This is one of the advantages of the apparatus; obviously no electrical energy is wasted. Insects are attracted either with sugar water or any other attractive substance. At night time electric lights can be used. The glare of sh ining metallic parts will also serve as an additional attraction. As soon as the insects touch the bait or the light, and coma in contact with any two of the naked wires, they are electrocuted at once and drop down to the bottom of the trap. The current passes only for an instant, and is very feeble.

—Peaty Water and Lead Pipes.—

The Local Government Board has re- i peatedly undertaken investigations relating ! to the tendency of water derived from | peaty soil to dissolve the lead of pipes and thus cause danger to the consumers. From a voluminous return relating to English water undertakings which has just been published, it appears that now nearly all the water from moorland sources is carried through galvanised iron pipes, or is treated with soda, lime, whiting, or chalk. This treatment, indeed, has been made a statutory obligation in pome recent local Acts. It is admitted, however, that water derived from a peaty subsoil is not necessarily plumbo-solvent at ail times. The report docs not deal with private supplies, nor does it, of course, refer to the Highlands of Scotland, where many private pipes are led into houses from the hills above. Pro- ; bably not in all such cases are precautions ; taken against the possible presence of lead i in the water. —Blood Bread.— -s Professor Kober, of Munich, has published a little treatise on the utilisation of blood ns food, from which Die Umschau . quotes the following statements concerning I the use of blood in bread-making. For ! centuries blood bread has been the staff of life of the Esthonians of the Baltic pro- 1 vinces and their colonics in all parts of : Russia. It is made of rye flour, with an | admixture of at least 10 per cent.' of ( whipped hc-gs’ blood. In the vicinity of ; Pctrograd ox blood is also used. Blood bread is very nutritious, and is highly praised by Esthonian physicians because of its richness in organic compounds of phosphorous and nerve-restoring salts. Bread made with ox blood dries very quickly, but this defect can be remedied by the addition of potato flour, which is now a common practice in Germany. Blood bread is the most natural substitute for meat, and, | with Government control of the slaughter- | houses, it need cost little or no more than ordinary bread. According to the Frankfurter Zeitung, rye bread containing hogs’ blood lias long been used in Oldenburg. —Omens of War. — , In a recent number of L’Astronomie M. Camille Flamnrarion publishes an ingenious j memoir, illustrated with quaint woodcuts i from a sixteenth-century work on prodigies. I in which he shows that all the celestial I and terrestrial omens of war in which our ! forefathers so firmly believed duly ushered in the great conflict now raging in Europe. Those include (1) the total solar eclipse of August 21, 1914, visible in Europe and j Asia; (2) Delavan’s naked-eye comet ] known as the “war comet,” discovered at • the close of 1913 and destined to remain i visible for the next five years (from which : the superstitious might augur seven years j of war); (3) the transit of Mercury on No- | vember 7, 1914; (4) the fall of a 351 b ; meteorite in England last October; (5) the ; great Italian earthquake of January 13, j 1915; (6) a “tri-coloured” star, of which M. Flammarion promises to furnish particulars 1 later, only remarking for the present that it was an optical effect much exaggerated : by the popular imagination; and lastly all , sorts of remarkable weather, including a | wintry day in June of last year, with a I minimum temperature of 41dcg in Paris. )

It would be too bad to refute this accumulated evidence of the futility of modern science by seeking- for previous periods of ci year or so in which similar omens were manifested, and no war followed. —Sterilising Water at the Front. —

One of the reasons which account for tha comparative, immunity of the troops, both in too east and west fronts, from epidemic diseases has no doubt been the satisfactory moans that have been adopted in all the armies for sterilising water. Various simple methods, which are easily practised by the soldiers themselves, are in use. and it is interesting to note that the German military authorities are, according to the German technical press. Very satisfied with the results that have been obtained from the use of peroxide of hydrogen, as well as by tho use of a compound of which this substance is one of the ingredients. It j# said, by the way, that this compound, when added to water, will destroy cholera and typhoid germs in 15 minutes at summer temperature, and render the water fit for drinking purposes. It is supplied to the troops in the form of tablets, one of which is sufficient to purify nearly a quart of water. Another method that is being largely employed by the Germans is thA use of tablets containing permanganate of potash and tartaric- acid or bis.ulphato of soda. The use of permanganate for purify? ing purposes is, of course, well known, and the reason for the addition of one or other of tho additional chemicals named is that the oxidising properties of the permanganate become more active in the presence of an acidified' solution. These mixture# are also supplied to the troops in (he form of tablets, one of which is sufficient for about half a pint of water, and all tho soldier has to do is to dissolve the tablets in tho water and allow it to stand for la minutes, when the water will be ready for drinking. It need hardly be said that our troops are as well supplied with the means of purifying water as are the Germans, it is interesting to know something of tha methods employed by tho enemy. —lmportant Tropical Discovery.

An important discovery in connection with the disease of biljarziosis, one of the greatest scourges of the Nile Delta for thousands of years, has been made by Lieutenant-colonel Leiper, M. 8., Ch.B., a native of Kilmarnock, and an alumnus of Glasgow University. Lieutenant-colonel Leiper, who belongs to the London School of Tropical Medicine, announced the discovery in a lecture in London recently. He told his audience that the eggs of the worm which causes it were found in a mummy dating back 2000 u.C The disease is widespread throughout the population, and in one village, at any rate. 90 per cent, of the children were infected by it. It has been known for long that the disease was water-borne, and that infection occurred through contact with water. But the exact nature of the life-history of the parasite was not established, and hence no sure weapon by which it might be destroyed had been forged. Colonel Leiper set himself last January, when he reached Cairo, to examine large numbers of molluscs collected in the infected districts, it being surmised on scientific grounds that some form of snail might be the intermediate host of the worm. The result of these researches wa* that a mollusc with a shell resembling that of a snail, and about the size of a halfpenny, was found to be infected. This mollusc inhabits pools and ponds and small canals where there is vegetation. The eggs of thq worm pass from its human host into the water, they then enter the mollusc and undergo a process of evolution, and six weeks later the mollusc has become a disseminating centre of disease. It remains infected permanently. The new forms which are produced in the mollusc arc able to enter the bodies of human beings through the skin. Bathing or washing the hands in these pools is, therefore, a dangerous practice, yet Colonel Leiper showed a series of photographs which proved that the native population washes itself every day in the danger area. All that scorns to bo necessary is action on the part of the irrigation authorities to have the small pools filled up in the dry season. The molluscs will tbeh be killed off, and the worm, robbed of it* necessary intermediate host, will gradually become extinct.