THE PROGRESS OF SCIENCE. 



509 



Halls, of Queenstown, Cape Colony, 

 and was later, but independently, dis- 

 covered 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 asso- 

 ciated with the path of the comet, and 

 the position in which the earth chanced 

 to be at the time. From the inter- 

 stellar 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 imtil it had 

 already passed perihelion. At that 

 time it w^as visible in the morning. A 

 week later it was seen in the evening 

 sky. At one time, except for the in- 

 clination of the plane of its orbit to 

 that of the earth, it was moving di- 

 rectly 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 direc- 

 tions. 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 posi- 

 tion 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 Mer- 

 cury. 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 

 I'oyal Observatory, Cape of Good Hope, 

 and at the Harvard Station in Peru. 

 This adds one more brief but interest- 

 ing chapter to the history of comets; 

 but in spite of their frequent appear- 

 ance and the attention which they re- 

 ceive, comets still remain, in many re- 

 spects, one of the unsolved astronom- 

 ical puzzels. 



VITRIFIED SILICA. 

 One of the most promising of recent 

 developments in connection with chem- 

 ical 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 in- 

 soluble, 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 un- 

 workable, though in time past a few 

 have used it for small objects, and some 

 ten years ago Professor Boys intro- 

 duced the use of quartz fibres, which 

 have found several important applica- 

 tions 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 heat- 

 ing quartz in small pieces to a tem- 

 perature 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 tempera- 

 ture vrithout splintering. It is worked 

 in the hottest possible oxy-hydrogen 



