Page:Popular Science Monthly Volume 59.djvu/519

Rh Halls, of Queenstown, Cape Colony, and was later, but independently, discovered at the Peruvian Station of the Harvard Observatory and elsewhere. Its path lay about 20° south of the sun, so that it was especially well situated for observers in the southern hemisphere. It seems remarkable that so bright a comet could escape more general attention. Bad weather and its southern position in part account for this, but the chief reason is associated with the path of the comet, and the position in which the earth chanced to be at the time. From the interstellar spaces the comet swept into the solar system on the opposite side of the sun from the earth. On this account, doubtless, it was not seen until it had already passed perihelion. At that time it was visible in the morning. A week later it was seen in the evening sky. At one time, except for the inclination of the plane of its orbit to that of the earth, it was moving directly towards us, but, swung about by the sun's attraction, it passed between that luminary and the earth. By the middle of May the comet and the earth were moving in nearly opposite directions. For a large part of the time during which the comet was under observation, it was visible only in strong twilight. About May 5 its position was more favorable, and it was a splendid object. It has now passed out of sight. The comet is described by Mr. Innis, of the Cape Observatory, when first seen, as of a deep yellow color. The nucleus was condensed, and of about the same brightness as Mercury. It had a tail about 10° long, but no coma, or 'hair.' As soon as the comet had emerged from the evening twilight, early in May, its most unique feature became apparent. This was a faint secondary tail, which preceded the comet, as it left the sim, at an angle of about 40° from the primary tail, which had become double. The main tail at this time, according to Mr. Lunt, was about 7° long, while the faint one was three times as long, or about 25°. Between these two were also two other very faint tails. At no time did the comet approach very near to the sun, or to the earth. Good photographs of it were obtained at the Royal Observatory, Cape of Good Hope, and at the Harvard Station in Peru. This adds one more brief but interesting chapter to the history of comets; but in spite of their frequent appearance and the attention which they receive, comets still remain, in many respects, one of the unsolved astronomical puzzelspuzzles [sic].

One of the most promising of recent developments in connection with chemical and physical apparatus has been the discovery of practicable methods of working vitrified quartz. With all the serviceability of glass and porcelain, there is a real need for some plastic material, more infusible, more insoluble, more fully transparent, more elastic, and more stable under changes of temperature than glass. These needs would be supplied by quartz, were it not for the great difficulty of working it. When touched with the flame, quartz splinters so badly as to be almost unworkable, though in time past a few have used it for small objects, and some ten years ago Professor Boys introduced the use of quartz fibres, which have found several important applications in the physical laboratory. To Professor W. A. Shenstone, however, belongs the credit of having rendered practicable the working of quartz into more or less complicated apparatus. The most important step in his process is the preparation of a non-splintering silica, which he accomplishes by heating quartz in small pieces to a temperature of about 1,000°C. and then throwing it into cold water. The white, enamel-like mass obtained can then be subjected to any changes of temperature without splintering. It is worked in the hottest possible oxy-hydrogen