Page:Popular Science Monthly Volume 16.djvu/145

 "I had made a large number of platinum spirals, all of the same size and from the same quality of wire; each spiral presented to the air a radiating surface of three sixteenths of an inch; five of these were brought by the electric current up to the melting-point, the light was measured by a photometer, and the average light was equal to four standard candles for each spiral just at the melting-point. One of the same kind of spirals was placed in the receiver of an air-pump and the air exhausted to two millimetres; a weak current was then passed through the wire slightly to warm it for the purpose of assisting the passage of the air from the pores of the metal into the vacuum. The temperature of the wire was gradually augmented at intervals of ten minutes until it became red. The object of slowly increasing the temperature was to allow the air to pass out gradually and not explosively. Afterward the current was increased at intervals of fifteen minutes. Before each increase in the current the wire was allowed to cool, and the contraction and expansion at these high temperatures caused the wire to weld together at the point previously containing air. In one hour and forty minutes this spiral had reached such a temperature without melting that it was giving a light of twenty-five standard candles, whereas it would undoubtedly have melted before it gave a light of five candles had it not been put through the above process. Several more spirals were afterward tried, with the same result. One spiral, which had been brought to these high temperatures more slowly, gave a light equal to thirty standard candles. In the open air this spiral gave nearly the same light, although it required more current to keep it at the same temperature. Upon examination of these spirals, which had passed through the vacuum process, by the aid of a microscope, no cracks were visible; the wire had become as white as silver, and had a polish which could not be given it by any other means. The wire had a less diameter than before treatment, and it was exceedingly difficult to melt in the oxyhydrogen flame. As compared with untreated platinum, it was found that it was as hard as the steel wire used in pianos, and that it could not be annealed at any temperature."

Animal Mounds in the Pyrenees.—An interesting paper was read by Dr. Phené at the last meeting of the British Association, on a discovery of animal mounds in the Pyrenees. The author said that this discovery was, in a great measure, due to the description given by Sir Vincent Eyre in 1869 of a remarkable custom of burning living serpents at a particular spot in the Pyrenees, While investigating the region around this place of immolation, Dr. Phené found in certain directions indications which always accompany animal mounds. The churches abounded in features expressive of the subversion of a pagan faith, of which the serpent or dragon had evidently been the central point. Following the track where these indications were plainest, he had some upon mounds as distinct in resemblance to animal forms as any of the American mounds: they were altogether artificial, and shaped into an appearance of animal outline so real as to seem like life. In the parts forming the heads the chamber had been replaced by an arched chamber of Roman work, in another by a descent of several feet into the body of a small church. On the spire of the best preserved animal mound had been a tumulus in which, the curé of the church informed Dr. Phené, had been found several of the most primitive cinerary urns, containing bones, Celtic articles, and above them objects of the Gallo-Roman description, and again above these later or Christian Roman works. One of the most interesting of the latter had been laid aside, and the curé sought it out for Dr. Phené among some débris; it was the stem of an ancient cross, and on it were sculptured serpents—not in the usual position of subjection to a superior power, but evidently as being in a condition of supremacy; but, as there were also several dead ones represented, it might be that the sculpture figured the condition of the real serpents before and after the ceremony of burning. In the district there were many emblems of the serpent or dragon, and the mounds were distinctly of such a form. On the mountains overlooking these mounds were a number of stone circles, like those so well known in Britain, Dr. Phené promised to give further details in a paper which he was to have read before the Congress of Americanists at Brussels.