SCIENTIFIC.

Otago Witness, Issue 1970, 22 August 1889, Page 35

SCIENTIFIC.

— The condensing effeot of electricity upon steam has just been demonstrated by Professor Sorket, the electrician, at Genoa. In a darkened room he heated some water in a platina basin which was connected with an electric machine. Just above the surface of fche water was fixed the other polo of the electric stream which passed through the platina and the water. An arc lamp made the steam visible as it rose from the heated water. As soon as the machine was set to work, the steam was observed to fall down upon the edge of the platina basin and there condense itself, instead of rising as usual. When the point was brought close, to the surface of the water,,the generation of steam was completely stopped, although the water continued to boil. -—The aitesian wells of Dakota are, per* haps, the most remarkable examples of their kind which have ever been opened both as regards the pressure and the volume of the escaping water. More than 100 wells, from 500 ft to 1600 ft deep, are at present in successful operation in the district north of Yankton, and they yield a constant stream of water, which is -apparently never affected by any of the surrounding influences. The pressure of the water is abnormally high in many instances and up to 1801b per square inch has been registered by the gauges. The power is utilised in the more important towns for water supply, for. protection from fire, and for driving machinery, and a very considerable saving is effected by the adoption of hydraulic apparatus in place of the steam-engine. In the town of Yankton, for'instance, there is a very large turbine, which operates a tow mill by' day and an -electrio plant. by night, and it is driven entirely by water obtained in this manner. What with natural gas and artesian wells, it would appear that in some districts Of America one only had to drill fche earth to obtain a supply of all the primary sources of heat, light, and power. —The incrustation of steam-boilers has always been a matter of pressing importance to engineers, and many remedies have been proposed to obviate what is not only an inconvenience but often a source of danger. The incrustation is due to the mineral matter, chiefly lime, which is contained in all hard waters, and which is deposited on boiling, as we can see by looking into any kettle that has been in use for even a short time. A simple remedy has been tried by an Italian engineer, Col Potto, and it is said with complete success, in a boiler of twenty-horse power, containing 126 tubes. He introduced into the boiler every week two kilos (about 4|lb) of sugar, with the result, that after four months' continuous working, only a very thin film of incrustation was formed, and this was easily -removed by simple washing. Without the treatment with sugar, the same boiler had previously become incrusted in a period of: six weeks. The method has the merit of simplicity and cheapness, and many will therefore be disposed to test its efficacy. — Chemists have for a long time been endeavouring to find a good artificial substitute for quinine. They recently thought they had found it in antipyrine, or, to give it its full chemical title, dimethyloxyquinidine, one of the many products of coal-tar ; but now they find that another coal-tar product, with a still more forbidding name, serves the purpose better. IToi short they call it antif ebrine. Coal-tar now, therefore, gives us besides a good substitute for quinine, our powerful disinfectants, our artifical sugar (saccharine), and many other things ; and a Berlin professor the other day went so far as to assure his class that from coal-tar he believed he could brew nearly as good a cup of tea as from tea leaves. Bat one should remember that the tea which will please the average German palate would be thought weak and very insipid by an Englishman, and, yet more so, by an English woman. — Edwin Chad wick is a name known to not many people outside the ranks of sanitation enthusiasts ; but the fact that sanitary science is beginning to secure the attention, of politicians is shown by the conferring of a knighthood on the old man after his 60 years of continuous labour in the cause of public health. Few men have ever led so quietly a reform movement resulting in such splendid achievements. Since he started to agitate for improved .sanitation the sanitary engineer has reduced the English mortality to a half of ■ what it was, and has added eight or ten years to ,the average English life. It is hardly possible to grasp the whole meaning of such results; even expressed as a mere annual money gain to the nation they would be dazzling. And although it is more difficult to detect the indirect influence of the national health on national crime, there can be no doubt that if the national body is kept sounder, the national mind must become so, and part of the diminution of crime in England during the last 50 years is certainly to be accredited to the sanitary reformers. — A tunnel on the Ehondda and Swansea Bay railway, Wales, has just been completed. It is two miles in length and runs through such a mountainous country that it was impracticable «to drive any shafts into it from above during the progress of, construction. In spite of this, when the two headings which were driven from both ends met, the one formed a perfect continuation of the other, and the levels did not differ to the extent of half an inch. The object of thia railway is to connect the extensive coalfield of the Rhondda Valley with the port of Swansea. — A novel experiment in popularising ecience is being tried in Berlin, where a company- has erected a popular observatory equipped with the ordinary astronomical instruments and also with elaborately got up panoramas illustrative of all the phenomena of solar and lunar eclipses. It is desirable that the general public should get something like a real grasp of the motion of the earth in the heavens instead of a mere formal acceptance of the statement of astronomers without any actual comprehension thereof. — The following incident happened in one of the public schools :~Teacher : " Define the word •excavate.'" Scholar: "It means to hollow out." Teacher : " Construct a sentence in which the word is properly used." Scholar ; •' The b£by excavates' when its gets hurt. ' (Continued, on page S7.} v . \[