Science Sittings

New Zealand Tablet, 25 September 1913, Page 53

Science Sittings

By * Volt.’

Blasting With Water. Herr Carl Meissner a German mining official, has devised a method of blasting coal by means of water instead lof powder that may greatly diminish the frequency, of mining disasters. According to the Journal of the American Medical Association, the apparatus consists of a long nozzle that fits exactly into the hole bored by the miners for the insertion of powder. The injection of a few quarts of water drives out the. gas in the coal, and then the injection of a little more water cracks and breaks the coal, so that a blow of the pick brings it down. The new method is extensively used in Germany, ;and several mine owners in the United States and in Canada are said to have adopted it with success. Substitute for Marble. A citizen of Reichenberg, Bohemia, has invented a process for producing a substitute for all classes of marble, including the most highly prized Italian, Egyptian, and Salzburg marbles. The claim is made that this product is superior to genuine marble, being stronger, more substantial, and less liable to crack or damage, and that especially in working, boring, or in installation work the danger of injury is much less than with real marble, while it costs only one-third as much. This artificial marble is made partly by hand and partly by machine. The cutting and polishing is done by machinery, the process being already, in operation in Vienna, Berlin, Mannheim, and Hamburg. Expensive Articles. Saffron would strike an ordinary observer as decidedly expensive at fifty-six shillings a pound until told that it is composed of the central small portions only of the flowers of the crocus, 70,000 of which it takes to yield the material for one pound. Otto of roses sells at an exorbitant price per pound, and it takes 10,000 pounds — nearly five tons—of roses to obtain one pound of the oil. Aconitine, extracted from the root of the monkshood, is said to be the very strongest poison extant, the dose being one six-hundredth of a grain. It is sold at the rate of £27 per ounce The musk of the Asiatic deer, at £6 to £7 per ounce, must be a prize to the wily hunter. In some of the tropical seas a floating, sweet-smelling mass of ambergris is met with, worth £5 10s per ounce, or £BB per pound, in the market. This ambergris is said to be the ‘ diseased biliary product ’ of the whale. Another peculiar animal product in use as a drug is a solution of the pure venom of the rattlesnake, given occasionally in malignant scarlet fever. The Gas Industry. Lecturing before the members of the Institute of Chemistry at London University College on ‘ Chemistry on Gas Works,’ W. J. A. Butterfield said the requirements of a public gas supply at the -present day were that the gas should supply the greatest number of heat units at the lowest cost that it should not have a strong smell, should give a flame having some natural luminosity, and should not yield on combustion products harmful to life and destructive to property. Dealing with the rapid growth of the gas industry, he gave the world’s production of town gas in 1912 as 620,000,000,000 cubic feet, in the manufacture of which about 60,000,000 tons of coal had to be consumed, while 30,000,000 tons of gas coke, about 3,000,000 tons of tar, and the equivalent of 550,000 tons of sulphate of ammonia would be produced. The estimated annual consumption of gas per head of the population in the world’s chief capital cities showed that London still headed the list with over 8000 cubic feet, as compared with 6000 cubic feet in Amsterdam, Berlin, New York, and Paris. This, increase in gas consumption was due to its greater use for heating purposes, and although it was not to be expected that the same rate of increase would be continued, there was little' doubt that

by 1920 in all the capital' cities of the world the consumption would be about 10,000 cubic feet per annum per head. v -