SCIENCE NOTES.

Otago Witness, Issue 2369, 27 July 1899, Page 54

SCIENCE NOTES.

j —In noticing the recent disastrous explosion at "St. Heldris, the "Jbtirnal of Gaslighting " took the opportunity to confute the assertion that gasholders in a town are a standing source of danger from fcheir liability to, explode. During the bombardment of- Paris the Governor of the city feared that the holders of the Villette station of the Gas Company would endanger the fortifications. He was assured that there was not the smallest risk — that, in the event of a projectile penetrating a bolder and firing the gas, th<; latter would

simply burn itself out as a jet of flame. Curiously enough, a shell shortly afterwards pierced the holder at Ivry, and ignited the gas. There was an enormous flare for about eight minutes, and then all was over. But at La Villette a shell penetrated a holder when it was full of gas, and actually burst inside .without setting fire to it ; and there was a similar occurrence at Vaugirard. These facts, which are specially noteworthy at the present juncture, were recently recalled by the perusal of the interesting and exhaustive address delivered by Mr Charles E. Monroe, the president of the American Chemical Society, at the New York meeting of that body.- Mr Monroe was dealing with the subject of explosions caused by commonlyoccurring substances ; and he characterised as "vulgar" the opinion that illuminating gas is an explosive. Of course, every chemist knows perfectly well that it is not, per se, and that it cannot be made to ignite unless in -contact with air or other supporter of combustion. But while the chemist and the gas manager are thoroughly cognisant of this scientific truth, and are able to demonstrate it, it is highly satisfactory to be in a position to adduce results of experience on a large scale so much to the point as those above cited.

— A young Frenchman has invented a primary cell which is said to give 13 amperes at 2 volts for a longer time than the ordinary bichromate cell or the Bunsen cell. Its essential characteristic is that a vanadium salt or vanadic acid is contained in the exciting fluid or in the substance of the negative or positive electrode. Such an element consists preferably of an external vessel containing a solution of 20 parts of NaCl to 100 parts of water, in which an amalgamated zinc rod is dipped ; an inner 'porous jar for the reception of a carbon plate, and which is filled with a mass of powdered manganese oxide and fused vanadic acid. This jar contains also a solution of sulphuric acid, vanadic acid, and hydrochloric acid. Ten per cent, of sulphuric acid may also be added to the NaCl solution in the external vessel. The depolaiisation is very energetic on account .qf the combined action of the hydrochloric acid, the oxygen, and the chlorine. Moreover, the reducing effect of the hydrogen is regulated by the presence of the vanadic acid, since this passes into- hypovanadic acid, and is immediately again oxidised to > .vanadic acid by the hydrochloric acid, while the hydrochloric acid liberates an equivalent of chlorine and four equivalents of oxygen. An addition of 10 per cent, of bichromate of potash to the acidified solution increases the output. Special cells have been designed for application to motor cars. — Electrical RevieTr. — "Rv ihij aid of improving machinery,

that which at the beginning of the century was the luxury of the rich is now the comfort of the poor. Material and labour are no longer the sole factors of production. Assisted by machinery and tools, man's labour now converts the raw materials of nature into the useful, necessary, and, in some cases, even the artistic paraphernalia of civilisation with one-third of the exertion formerly necessary. Even Russia, the latest competitor in flic industrial field, has, with the aid of machinery, more than doubled, since 1861. the individual output of those employed in her manufactories. In the course of 20 years (1870-1890) the number of persons employed in the. American manufactories has more than doubled, and the value of their product has nearly trebled. These facts show the important part that machinery now plays in modern industrial warfare. Few realise or stop to think how much we are indebted to the inventor and machine designer for the comforts, luxuries, and necessities of our dn-ily life. The loom which weaves our silks, cottons, 'and woollens ; the harvesting machines which reap our corn ; the machinery which forms our bricks and mixes our mortar ; the printing machine which makes the penny daily possible; our food, clothing, furniture, literature — all -are produced on machinery which it is practically impossible to make or maintain without the . modern machine tool. — Engineering Magazine for June.

— The sun-bath is a very old remedy, and was supposed in ancient times to be beneficial in vai-ious ailments ; and in these more modern days it has been proved experimentally that various germs grouped under the name bacteria perish under the action of sunlight. The electric light is now being used in Germany for curative purposes ; and quite recently at the Peebles Hydropathic establishment baths made on the German model have been introduced. The bath contains the necessary electric light apparatus, and is lined with mirrors, by which the rays are reflected upon every part of the body. A lid covers the bath, and the patient's head only is not exposed to the action of the light. The heat also from the lamp or lamps does its part, for the patient perspires as copiously as if he were in a Turkish bath. The effect of the treatment is said to be most invigorating.

— One of the most interesting men at The Hague just now is not directly engaged in the Peace Conference. This is M. de Bloch, whose monumental work upon war is s-aid to have inspired the Czar's Rescript. M. de Bloch, however, modestly disclaims this honour. He does not believe in the "humanising " of war, which, with every new firearm, grows more deadly.. The action of the new projectile on the human body is, he has stated, fearful, resembling the action of an explosive bullet. The bones are not pierced as with an awl. To think so is erroneous. On the contrary, they are splintered into tiny fragments, which are scattered throughout the entire organism with the force of a dynamite discharge. The entrance made by the bullet is small, almost invisible, but its exit is marked by a gaping wound. It does not pierce one body alone, but has the power to penetrate three, and its course is only stopped in the fourth body. Liver, heart, and kidneys, when touched by one of these projectiles of the future, are pulverised, and the other internal organs, especially the muscles, are torn to pieces. The extremities, if a bone is struck, are destroyed, and wounds in the head, neck, and abdomen are always fatal.

— The effects of the persistent use of strong coffee are most marked. They show themselves in profound mental depression, insomnia, and severe headache. There is muscular weakness and trembling, irritability of the heart's action, with sensation of weight. A form of dyspepsia occurs also, which is peculiar and persistent, as long as the agent is continued. When the coffee habitue undertakes to stop the inordinate use of the decoction, there is constant fear of death, which is only relieved by resorting to the agent again. The face becomes sallow, the hands and feet cold. Erysipelas and other acute local inflammations are easily induced. The party who is a habitue to the inordinate use of coffee resorts "to the use of alcohol also, "to preserve the stimulating effects. People suffering from neurasthenia and general nervous prostration are most likely to form the habit of the inordinate use of this beverage. In extreme cases of melancholia, the mental depression becomes so great that suicide often follows. Snaitken, according to the Medical Review, says that the "Moors ore inveterate coffee drinkers, especially the merchants, who sit in their bazaars and drink continually during the day. - It has been noticed that almost invariably when these coffee drinkers reach the age of 40 or 45 their eyesight begins to fail, and by the time they are 50 years old they become blind. One is forcibly impressed by the number of blind men that are seen aboul the streets of the city of Fez, the capital of Morocco. It is invariably attributed to the excessive use of coffee".