Science Siftings

New Zealand Tablet, Volume XXXVII, Issue 3, 21 January 1909, Page 115

Science Siftings

BY 'VOLT

Ice Sticks. •' '" ~^\ In Austria ' Ice sticks ' are manufactured, at a profit. A .series of poles is arranged so that the water will fall slowly over each one in the series. Of course, the water in the winter time freezes, forming large icicles." When the icicles have attained the proper size the employees of the ' ice plant ' come around with carts-, break off the great sticks of ice'and haul them away to a place where they "are '• put in storage. Of course it is much ea,sier v to handle a large qiiantity of ice in this way than it is to cut it from - some stream and then pack it away. There may, however,, be a difference in quality between stick ice and lake or river ice. The World's Coal Supply. ' The question of the exhaustion of the coal supply of the United States is not one which can affect the present generation or the next (says Harper's Weekly). Yet the American supply is likely to be exhausted before that ' of- Europe, and particularly before that of Great " Britain. It has been estimated that Pennsylvania has about enough anthracite coal to last at the rate of production that prevailed last year a little less than two hundred years. Probably the supply will be exhausted much sooner than that, unless some profitable substitute is found for anthracite. As to bituminous coal in the United States, the supply vs very great and widespread. It is estimated that it will last, at the rate of consumption which prevailed .during the last decade, something less than 450 years. If the coal supply of the world at large were likely to be exhausted in any such way as to make a considerable drain on American coals for foreign consumption the situation might be regarded as alarming if we could place ourselves in the.,, place of our great-grandchildren. But there is not likely to arrive a time when we shall have to ' feed the world ' with coal. In 1880 Great Britain had 'in sight,' so.lto.= speak — although it was all below the ground — an available coal deposit estimated at nearly 145,000,000,000 tons. At the rate of production and consumption then prevailing the supply would last about 900 years. The coal measures of Lancashire are 9000 feet in thickness. Moreover there are many countries which possess coal deposits that have never been touched. ~ Besides the great coal fields of Europe and America, as now worked, there are undoubtedly coal deposits in China, in the Philippines, in Australia, in South America, in British North America, - in Alaska, in the Indian Archipelago, and elsewhere. Silk Culture in China. Shan-tung, China, is noted for the "qifantity of raw silk that it furnishes annually to all the silk manufacturers of the world.. The southern and western parts of this province have thousands of silk but Linklinis the chief centre of the industry in the Chinese Empire. Valleys and mountains are covered with mulberry trees. The nature of the soil marvellously favors their growth and the luxuriance of the foliage upon which the silkworms live. The trees p#t forth their first buds about the end of April or the beginning of May. The appearance of the leaves coincides with the hatching of the larvae. The evolution of the silkworms and the formation of the cocoons are watched over with great care Jby the seri-culturisb. Then,, in time, comes the process of boiling, beating, and gathering, or winding, the silk by laborers. During -*a . s working day of twelve hours a laborer winds about two Chinese pounds of silk. Before being taken from the reels the silk is allowed to dry; then it is made into skeins, and is ready to be sold. The quality of this silk, which is usually of a golden yellow color, though sometimes greyish, is excellent. It is carried to market in small quantities at a time. Perhaps the reason for this is that many robbers infest the roads on the eve of market day and on, the day itself. The great silk market is at Ts'ing-tchsou-fou. It is held every fifth day during July and August, and afterwards less frequently until mid-November, because of the autumn harvesting. The vendors repair to the market ih^ little companies from each village, in order that, being "together, they may resist the robbers, if attacked <nu the way. Sometimes they journey thus twenty, fifty, or a hundred lis to sell their silk. . The price per pound varies from day to day according to the quality and. quantity of the silk to be sold. Last year the average price was ,a sum equivalent to about 12s a pound.