Page:Science vol. 5.djvu/370

 tVoii. T., Ko. Irt.

��A TYPHOON IN SICILY.

In the early morning of Hie 7th ot October, 1884, Etna was seen lo be cohered with a mantle of clouds, wbicb sprciil ibemselvea in a nonh-west direction. At eight o'clock there waa a barometric depression throughout the whole weBteni part ot Sicily, the mer- cury falling two millimetres. Daring the typhooa, which began at about noon, the barometer registered 7S1.1 millimetres, whereas in the morning at nine o'clock it Blood at 761.8 millimetres. The normal average Is 702.5 millimetres. The thermometer at nine o'clock was 22.5° C, and during the storm went up gll^tly, The relative humidity at nine was 0.76,

���CREEPING OF RAILS.

It has been observed by those having charge of railroad -IJ-acks. that In some places the rails more longltudiimlly, or 'creep.' On double- tracked line* the rails tend to move in the direction of the tialBc; but on tingle-tracked roads the alternating direction ot the trains will naturally neutralise this t^ndeocy. Again: on long inclines or grades the track may creep down hill, — a phenomenon which is reasonably attributed lo expansion and con- traction from successive changes of letnperk- ture, the rails slipping in the direction of least resistance; that is, expanding down bill, and contracling up hill. In botli cases there is generally little difficulty in arresting the move- ment by driving spikes Into the ties through the notches provided for this purpose, either in the rail-flanges at or near their enda, or In the angle splice-bars so com m only used at Joints. The rail often exerts con'ldeimble force against these spikes or bolts, and baa bt'en known, In some Instaiices, to partially

��(Pmiu la Hatm

but St noon had risen to 0.8S. At eight o'clock the wind was from east-north-east, blowing gently, and at noon was from the south-east. At 12.-tr>, near the Posso Por- tose, 18 kilometres from Catana, a dark cloud In the form of a spout was seen to form. The rotary movement was opposite Chat of the hands of a watcli. and the spout trav- elled across the cuntry from west-soulh- west to cast- south-east at the rale of 2K kilo- metres (17 miles) per hour. It frequently raised itself above the ground for some mo- ments, and theti again touched the land to complete lis devastation. When near Ogni- na, It left the land and went to sea, where It died out. The noise produced by the storm has been compared to that caused by many trains of cart passing over an iron bridge al high speed. There were very few flashes of lightning, and only two reports of thunder loud enough to be heard above the storm. Hail- stones of greal si^e fell on the northern border of devastation, causing much damage. They were very rough, anil some were as Ut^te as oranges. One weighed SW grams. The xone of greatest devasta- tion was about 27 kilometres in length (not includ- ing the 5 kilometreit at sea), with a breadth of 350 metres. Twenty-seven inhabitanls were killed, and five hundred wounded. Many houses weredestroyod, trees torn up by their roots and carrieil away, and In one place a piece of lava weighing 8 kilograms was

����cut or shear them off. The thrust is rssiated b]r tl ballast in which the ties are bedded.

A curious Instance of rail -creeping, which It is dtflt cult to explain, was given in the Railroad gatetl ' Dec. 5, 1884, where it is staled, that on a piece of gle track on the New- York and New-England railro near Hartford, Conn., n part of which was level, antf™ the rest on a grade of twenty feet per mile, with an equal number of trains each way, one rail moved down hill live feet and one inch in the course of k year, and the other moved eighteen inches In tlie reverse direction. It lias been suggested that the spllica in the two endi ot the ties or sleepers may not have been properly alternated, thus allowing the tie* lo turn horizontally from the correct poailion at right _ angles to the raits.

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