1865.] Prof. Phillips Physical Aspect of the Sun. 47 



history of these ephemeral phenomena, that no view of their origin and 

 progress can be held to be so well established at present as to exclude the 

 consideration of other speculations. 



Faculte. Near the edge of the solar disk, and especially about spots 

 approaching the edge, it is quite easy, even with a small telescope, to 

 discern certain very bright streaks of diversified form, quite distinct in 

 outline, and either entirely separate, or coalescing in various ways into 

 ridges and network. When, near the limb, the spots become invisible, the 

 undulated shining ridges and folds to which I refer still indicate their place 

 being more remarkable thereabout than elsewhere on the limb, though 

 everywhere traceable in good observing-weather * (see Plate III.). Faculse 

 are the most brilliant parts of the sun ; they appear of all magnitudes, from 

 barely discernible softly gleaming narrow tracts 1000 miles long to conti- 

 nuous complicated and heapy ridges 40,000 miles and more in length, and 

 1000 to 4000 miles broad. By the frequent meeting of the bright ridges, 

 spaces of the sun's surface are included of various magnitudes and forms, 

 somewhat corresponding to the areas and forms of the irregular spots 

 with penumbree. They are never regularly arched, and never formed in 

 straight bands, but always devious and minutely undulated, like clouds in 

 the evening sky, or irregular ranges of snowy mountains. "When care- 

 fully studied with powers of 75, 135, and 180, which are very effective, 

 the ridges appear prominent into cusps, and depressed into hollows ; the 

 cusps having brighter and more shady sides, so as not to be unlike some 

 forms of branching crystallized native silver. 



Ridges of this kind often surround a spot, which appears the more con- 

 spicuous from the surrounding brightness ; but sometimes there appears 

 a very broad white platform round the spot, and from this the white 

 crumpled ridges pass in various directions (see Diagram, October 16, 

 1862, No. 2). Toward the limb the ridges appear parallel to it; further 

 from it, this character is exchanged for indeterminate direction and less- 

 ened distinctness ; over the remainder of the surface they are much less 

 conspicuous, but can certainly be traced as an irregular network, more or 

 less disguised by the minuter structure which has been described as 

 porosity. I present selected sketches of the appearances mentioned. In 

 considering the faculse with attention, I remark that they preserve their 

 shapes and positions with no material change during a few hours of ob- 

 servation, and probably for much longer periods, since after rotation 

 through 15. the main features appear much the same as before. 



The faculse look like half-shaded snowy mountains and like half-illu- 

 minated clouds, and one might suppose that in either of these cases their 



* In a recent communication to the Royal Society (Proceedings, vol. xiii. p. 168), Mr. 

 Balfour Stewart remarks that, in the photographs of the sun taken at Kcvv, it appears to 

 be a " nearly universal law that the faculse belonging" to a spot " appear on the left of 

 that spot, the motion due to the sun's motion of rotation being across the picture from 

 left to right." 1 find that my sketches support this view to the extent that the faculae 

 which follow a spot appear in several cases more prominent than in others. Perhaps 

 in a photograph those only can be traced, or the differences may seem to be greater. 



