Science Siftings

New Zealand Tablet, 11 March 1915, Page 41

Science Siftings

By ‘ Volt'.’

Marvellous Preservation. It is marvellous what an almost perfect condition prevails along a large part of. the great wall of China. The bricks of the parapet are as firm as ever, and their edges have stood the severe climatic conditions of North China with scarcely a break. The paving along the top of the wall is so smooth that one may ride over it with a bicycle, and the great granite blocks with which it is faced ax smooth and as closely fitted as when put in place over two thousand years ago. The entire length of this wall is 1400 miles, it is 22 feet high, and 20 feet in thickness. At intervals of 100 yards or so there are towers some 40 feet in height. Ignis Fatuus. The Latin term, ignis fatuus, which literally means, according to the dictionaries, ‘ foolish fire,’ ‘ fools’ fire,’ ox ‘ vain fire,’ was not so common in old-time English books as its equivalents: £ Will-o’-the-Wisp,’ ‘Jack-o’-lantern,’ etc. These names refer to a luminous appearance of a feeble light sometimes seen during summer and autumn nights flitting in the air a little above the surface of the earth, in marshy places, near stagnant pools, or in churchyards. Many efforts have been made to discover the cause of this light; but it appears in so many different ways arid so void of any common principle that the attempts can scarcely be called successful. Perhaps the commonest form in which ignis fatuus is observed is a pale, bluish-colored flame floating in the air about two feet from the ground, a little after sunset till the following morning. Sometimes, instead of shining uninterruptedly, it appears and disappears at half-hour intervals. At times it remains fixed at one spot, and again it travels with great rapidity. One plausible explanation of the phenomenon is that it is caused by the decomposing of vegetable or animal matter which in a marshy soil generates or produces little jets of gas that possess the property of igniting or taking fire when they come in contact with the air. Quills and Pens. It is only in old pictures that we see the goose quill pen nowadays, its feathered shaft looming white above an old-fashioned clay ink bottle. Yet our grandfathers knew xxo other instrument. Steel pens are in common use only a comparatively short time. A story long taken for granted gives the honor of their invention to a well-known manufacturer. In 1830 he was a journeyman jeweller in England. One day he accidentally split a fine steel tool. Shortly afterward he was called upon to sign a receipt, and as he had mislaid his quill pen he took up the piece of pointed steel and was very much surprised to find that it wrote better than the quill. He was quick to see the great possibilities. He began the manufacture of steel pens. While he may not have been the original inventor, we are indebted to him for their general introduction. His claim of having produced the first steel pen has long been disputed by Germany. A manuscript dated Nuremberg, 1544, strengthens the latter’s claim considerably, as the resurrected document is said to contain a description of pens produced from copper and brass plates, as well as from iron and copper tubes. But however much truth there may be in this old German manuscript, there are many men living who can remember when there were no steel pens, and can also recall the time when one of the regular duties of the schoolmaster was to repair all the quill pens used by the scholars.