Scientific and Useful.

Lake Wakatip Mail, Issue 1582, 25 March 1887, Page 4

Scientific and Useful.

BLKCTRICIL METROffOMK. An elrctriral metronome has been established at the Paris Opera Hohso, which enables the chef d'orchettre\to conduct choruses at any distances from his chair. The working i* very satisfactory, and the effect really admirable. SUVEBISG HON. An ingenious process for giving a silver surface to iron has recently been devisod in Austria. The iron is first covered with mercury, snd silver is deposited upon its surface electrolytieally. The iron is then hrated toabiut 300 deg. C , and the mercury evaporates, leaving the laver of silver on the surface of the iron. LTJ3IISONS CLOCD. Between 8 and 9 o'clock on November 3 a remirkahle phenomenon was observed at Hainan in Norway. At the time there was perfect darkness, when, suddenly, a bright white cloud appearesl in the sky, drilling in a north-ea»terlv direction, and from time to time emitting brilliant rays of light in various directions. The cloud retained throughout its original form, aDd disappeared at last in the darkness. TKLEOLOOY. A correspondent of the Nature in South Africa writes:— Rogeria lo»gi/ora, the Martynia-like plant, has cnp?ules which pierce the lips of the gun or' wildebeest,' and are rubbed to pieces in their efforts to get rid of them. Truly what with Uncaria, costing the life of a springbok for (very capsule trodden out, and Kogeria festering in the poor "wildebeest's mouth, the beneficent ' Nature' te'eo'.ogist is in Africa a remarkably cruel divinity." prBITT OF MID-ATLAXTIC AIR. The purity of Alpine air has been demonstrated by Prof. Tyn'iall and others, and a similar claim is made for the ar of the midAtlantic. Lecturing recently on the action of micro organisms on surgical wounds, Prof F. S. Dennis, of New York, st.ted that during his last trip Bcross the Atlantic be made some experiments to test the purity of the air about 1000 miles from land. He employed capsules of sterilised gelatine, and exposed them for fifteen minutes. Ore capsule was exposed in the stute room upon the main deck of the steamer. Within 18 hours over 50 points of infection had developed. Two capsules exposed in a similur manner in a cibin on the promenade deck, where the circulation of the air was free, showed five or six points of infection each ten days afterwards. A capsule ciposed over the bow of the ship was found to be entirely uncontaminated. THE IBIS. The intelligence of the ibis is well known, and those who have been along the Spanish Main will perhaps remember its cleverness when in pursuit of the crayfish. In the dry season, when food is scarce, the latter burrows some three or four feet beneath the •urn* S, for he is not fairly comforta'da save in the damp or moist earth. Coming upon one of these burrows, the ebis tumbles the earth back into the aperture, and the crayfish shut off from the air, comes up to repair damages, and is seized by the ibis and devoured. The ibis was worshipped by the Egyptians, and reared in their temples. Some saw a connection between the changes of its plumage and the phases of the moon, while others, because the inundation of the valley of the Nile took place just after the return of the ibis, were inclined to attribute this common phenomenon to its coming; tracing the rise and spread of the stream, which attracted the hungry birds, a* the consequence rather than, as it really is, the cause of their appearance.—Scientific American. FLAME. It will be interesting to consider for a momert the cause of flame becoming luminous. This luminosity is due to free c.rbon, liberated by the hydrocarbons in the flame, being heated up to the temperature of the flame itself. These solid particles, becoming incandescent, act like tiny incandescent gas lights, each particle of free carbjn throwing out beat and light in all directions until consumed and converted into curbonic acid gas, which is transparent, and therefore does not radiate light and heat, although its temperaton may h»ve increased during the change. The free carbon is always the last component part of the dime to burn, and in cures of imperfect combustion, instead of becoming incandescent and luminous, it is precipitated as soot when deposited on chimney flues, and as smoke if carried along with tho products of combustion, which,issuing from chimney tops, is so very objectionable in our towns aud manufacturing dist'icts. TUB "AIBTEI-EGRAPH." The Edison-Oilliland Smith system of telographing to aud from trains without a direct connecting wire—the system described by Mr Edison as the " air-telegraph "—is now in use on the Chicago, Milwaukee, and St. Paul Kailway, only a few months after the first test at Staten Island. One car on each train is furnished, it appears, with an inexpensive instrument, and induction is relied upon for carrying the electric current from this instrument through the air to the ordinary Morse wires at the sido of the track. Construction trains on the St Paul road are provided with these instruments and operators to work them. A construction train frequently has 70 or 80 labourers aboard, and mu>t get out of all regular traffic along the line. Accordingly, such a train has to be constantly moved on to sidings, in order to leave the road free for passenger and freight trains. A OKEEK GIANT. A young Greek giant has been attracting the attention of the public at Trebizonde. This youn; man, whose name is Amanab, was born near Eeressond in 1868. He is 7} feet in height, the circumference of his head is _'''>; inches, and the girth of his body at the chest is 4 feet and 4 inches. Amanab, who is but 18 years of age, has perhaps not as yet reached his full development, and it is not impossible that he may grow still taller. He has no occupation. It is his intention to visit the principal cities of Europe, and exhibit himself to the public. Amanab, notwithstanding bis great size, has n >t yet reached that of certain giants to whom attention has been called at various epochs. If Buffon is to be believed, there have been giants who exceeded 81 feit in height; hut the fact has never been authenticated. In 1735 there was exhibited at Paris a giant who was 6 feet 8 inches and 8 lines in height. It will be seen that such height was much leas than that of Amanab. This giant was born in Finland, upon the confines of Southern Lapland. The giant of Thoresby, England, was 7 feet 5 inches in height. The Duke of Wurtemburg had a porter who was 1\ feet in height. A very remarkable Chinese giant named Chang was exhibited at Paris a few years ago. Ha was larger than the Greek under consideration, his height being 8 feet; and unlike his similars, he was intelligent, and educated, and spoke several languages. It will be seon from what precedes, that the Greek Amanab, I despite his respectful height, is far from being without a parallel.