SCIENCE NOTES.

Otago Witness, Issue 2303, 21 April 1898, Page 48

SCIENCE NOTES.

_ — Goldstein "was the fir« 6to discover that on;mon b'alfc is coloured brown and potas- • turn chloride violet by the action of cue ca ' ibode rays\says the Engineering and Mm - tng Journal) " 'Tilts discoverer attributed this phenomenon to some physical change under- ' gone^y the salts. Wiedemann and Schniidt itmfinted'it to 'their partial conversion into sub-chloride, and Giesel actually, succeeded in preparing similarly coloured, sub-chlorides in a chemical; way But" the^shemical hypo thesis -is now invalidated by the researches oi JR. Abegg He obtained the salts, in questiou in a pure and, finely-powdered state, so as to' bfr-abie -to colour them all 'through Itis first experiments showed that the colour- - ing' does not spoil the vacuum in the tube, as "Jt/vfould if chlorine- were evolved The salt? jvere rendered colourless again by high exhaustion producing rays wilh «)jsrong heathy effect. The substances cofrM l &> askujsd

and v uncoloured any number of times in succession. When the coloured salt was dis- ' solved it produced no reducing or alkaline reaction. When undissolved in a saturated # solution it retained its colour. All this tells against a chemical change. Moreover, an easily-reduced chloride is not reduced by the cathode rays. It is well to remember that ! the colouration of these alkaline salts is a phenomenon not produced by liglit. On the other hand, cuprous chloride is blackened by •light, but not" acted upon by the cathode rays. — Professor Barton has published an interesting collection of statistics which prove the influence that magnetism is exerting in "proving phenomena which 5 otherwise would . be inexplicable. Among other things, he . ■ shows that in making a railroad* running east ] and west, as many as 13 steel rails will be- j come chrystalised and break before one rail -| on .a north, and south* track is similarly affected. This is dite to the generation of magnetism by friction, and to the fact that in the former instance the polarity of magnetic cur- I rent is resisted in the rush of the train; ' whereas in the latter case it is undisturbed. 1 — The Marconi apparatus for telegraphing ) without wires has been considerably " im j proved, all that is now necessary being a tall pole from which a large cylinder containing ; the large coils and other attachments is sus- 1 1 pended, and connected by a wire to the in- j i struments in the inventor's room, a similar j ' pole and connection being erected at Tofcland i i Bay, near the Needles. The inventor is able ! [ to communicate from Bournemouth, where ] he is staying, with his assistants on the other -j side of the Solent, a distance of 35 miles, by j means of his new telegraphic system. ] — The North German Lloyd steamer Gera, ] which recently arrived in New York from ! Bremen, ran into a tempest in mid-ocean on i January 7, and shipped the crests ofWany \ combers. Her commander determined to try the efficacy of soft soap and oil on the waters. It is, of course, usual for storm-tossed vessels j to use oil in the quieting of troubled waters, I but the -combination of oil and soft soap is I rare. It was run from pipes on the weather f side, about 60ft abaft of the beam. -About eight gallons of soft soap and four gallons of -thick lubricating oil were used. The soft soap was dropped through one pipe and the 1 oil through another near by. A heavy ! lather appeared on the sea, and the crests I ceased breaking aboard. The storm modeI rated next , day, and the Gera was ' able to j. make her-»usual winter weather speed the rest , of the trip. — Scientific American, j — Professor Trowbridge, of Harvard Unii versity, recently had constructed a battery of j 10 ; 000 storage cells, with which he has peri foimed some very startling experiments in !' spark discharges. He computes the electrical ' potential necessary to produce 'a lightning . flash one mile long at about 1,000,000,000 volts, an almost inconceivable potentiality. ' His battery is used to charge a set of con- ' densers, which are then disructively discharged. j — Tijo much-sought-for alkahest, or universal solvent of the alchemists, is almost realised in fluorine, which was first prepared by Moissan in 1886 The transparent vessels in which it is contained have to be made of j some fluoride, its action on ordinary glass \ being very vigorous and destructive. The j difficulty of handling the gas, even in the , laboratoy, has hence been very great,' the \ fluoride vessels being brittle and clumsy, as : well as expensive. Professors D*y,wir and ; Moissan, being desirous of more fully mvesti1 gating the properties of the gas, recently j conducted a series of experiments at the I Royal Institution, in which by meaps" of liquid oxygen they succeeded in l.jyiying fluorine, and in this comparatively inert 6tate , could more fully and carefully examine its properties. The apparatus used for liquefying the- gas consisted of a small cylinder of thin glass, mto the upper part of which was fused a platinum tube surrounding a smaller tube of the same material. The fluorine enters through the larger tube, passes around ihe glass envelope, and escapes through the smaller tube. The glass cylinder being cooler] down to tlie temperature of boiling liquid ' oxygen { — 183deg), the current of fluorine gas J was passed through the bulb without becom- | ing liquid At this low temperature, how- { ever, the fluorine did not .attack the glass. On still further lowering the temperature of the liquid oxygen hy exhaustion a yellow liquid was seen collecting in the glass envelope. -\rhi3a ges no longer escaped from the appal sgsa, At this moment the escarje tube

was closed to prevent the entrance of air, and the glass bulb soon became full of a clear yellow liquid possessed of great mobility. Fluorine thus liquefies at about — 185deg The chemical activity of the gas was found greatly reduced when in the liquid state, but even then benzine or oil of turpentine underwent spontaneous decomposition when brought into contact with it. It would thus seem that the powerful affinity of fluorine for hydrogen is the last to disappear. In a subsequent experiment", in which liquid air was used and a temperature approximating — 210deg Obtained, the liquid fluorine showed no signs of solidification. Experiments to determine its density led to the conclusion that it had about the same specific, gravity as amber, 1.14. Different samples of the liquid examined with the spectroscope showed no specific absorption bands in the visible spectrum. It was found to be not magnetic. — A new kind of bullet has been offered to the Government. It is of lead, and instead of having a conical top is level-topped Avith a cup-like cavity, carrying the expansive principle to its greatest extent. Upon entering the flesh the front of the bullet acts \ like a punch, cutting a clear round Hole which does not, close up. .Expansion commences immediately, and after the bullet has travelled 6in it produces a jagged hole from j 3in to 4in in diameter. If this bulletf is ever j adopted it will be one of the most terrible j wound-producing missiles with which our j s-ldiers could be armed. • | — Attention has lately been called to the 'nvestigation of Dr G. S. Hall, president of (.'lark University, on the things that most : >ou,ie fear. Taking the subjects broadly, it -; speared that out of 298 classes of objects dseaded by 1707 individuals, thunder and Jjghtning were the ones creating the greatest alarm and anxiety And yet, as pointed out by one of the electrical journals, a thunder storm might compare with John Bright's express train as the safest thing on earth to be in. Records have been carefully kept oi accidents and deaths from lightning stroke or thunderbolt, and they are apparently on the decline, the period 1890-93 showing only 193 a year for the whole United States. On the other hand, 200 people are drowned iv New York City every year, 150 are burned or scalded to death, and 500 die from falls of various kinds, it is the rarest thing in the world, literally, for any one of Greater Xew York's citizens to be killed by lightning, and yet when a thunderstorm invades this region most of the three million inhabitants are decidedly fearful and uncomfortable The statistics show that, in respect of immunity from accident by lightning, the modern city is infinitely safer than, the open country. — Scientific American.