SCIENCE SIFTINGS

New Zealand Tablet, 14 March 1918, Page 46

SCIENCE SIFTINGS

By “Volt."

The Giant’s Causeway. ; The Giant’s Causeway is a natural pier or mole of columnar basalt projecting from the North Coast of Antrim, into the North Channel seven miles north-east of Portrush. It is part of an overlying mass of basalt from 300 to 500 feet in thickness, which covers almost the whole county of Antrim, and the eastern part of Londonderry. It derives its name from a legend that it was the commencement of a road to be constructed by giants across the Channel of Scotland. Which is the Greatest Volcano? Mont Pelee, an active volcano situated in the north-western part of Martinique, in the West Indies. Prior to the terrible eruption of 1902, the elevation ofthe mountain was 4300 feet and the summit was occupied by beautiful and rank vegetation. On May 8 of that year the volcano threw up a tremendous column of explosive, and exploded superheated steam, ashes, and glowing blocks fully 1500 feet in diameter at a velocity of 100 miles per hour. The city of St. Pierre and its thirty thousand people were wiped out instantly, only two inhabitants of the city proper seem to have survived. The most remarkable feature was the great mass of rock, 300 feet wide, a veritable obelisk, pushed upward 800 feet from the new crater. Another greater eruption occurred on August 30, 1902, and was extraordinary in its wide disturbance of the magnetic field, which was transmitted to the antipodal region of the earth in two minutes’ time. The noise of the explosion was heard at a distance of 850 miles. Crystals and Crystallisation. In the course of his presidential address before the Microscopical Society, Christchurch, on “Crystals and Crystallisation,” Mr. E. E. Stark said that it was a common and instructive experiment to place a delicate framework of a basket or some other object, in a solution of sugar or alum; after a while it became a basket of finished gems, the crystals glistening with their many polished facets. Again, if a quantity of sulphur were melted, it would crystallise on cooling. To obtain distinct crystals, the surface crust should be broken as soon as formed, and the liquid part within be poured out ; the cavity, when cold, would be found to be studded with delicate needles. The crust in this case was as truly crystallised as the needles, although but faint traces of a crystalline texture were apparent on breaking it. This was owing to too rapid cooling. Melted lead and bismuth would crystallise in the same manner. There was a substance, iodine, which, when heated, passed into the state of a vapor; on cooling again the glass vessel containing the vapor was covered with complex crystals as brilliant as polished steel. During the cold of winter, the vapors constituting clouds, often became changed to snow; this was a similar process of crystallisation, for every flake of snow was a congeries of crystals, and often presented the forms of regular six-sided stars.