478 Prof. Phillips on the Surface of the Sun. [Nov. 23, 



PL XII. fig. 1 represents a part of the surface under a low power (75), 

 which is carefully moved out of focus inwards and outwards. Under these 

 conditions, the soft undefined mottling which it shows catches the eye, and 

 appears clearly to be caused by parts not differing in structure from the 

 more shadowy spaces between them, except by there being less effect of 

 shadow points and lines on the parts which are relatively lighter. Here 

 and there apparently dark specks appear, either in the darker tracts or on 

 the lighter parts ; and there are specks of all degrees of darkness, as well 

 as lines of greater or less distinctness. 



PI. XII. fig. 2 is offered as a careful attempt to copy a definite tract, still 

 employing a low power (75), and using every means to get the focus exactly. 

 When this is accomplished, and the eye placed as close as possible to the 

 eyepiece, the appearances can be sketched as well as an artist can picture 

 a tree with its leaves, a heap of broken stones, or some dissected and areo- 

 lated clouds. They can be sketched, but certainly not well or truly, 

 without patient attention, and eyes and head in a good state. Here the 

 texture appears to be areolar, with much irregularity in the shapes, but no 

 great inequality of size. Dots of extremely small dimensions, sometimes 

 quite black, appear singly or in pairs in the centres of several areolse. 



PI. XII. fig. 3. Another sketch, under the same conditions, but employ- 

 ing powers of 135 and (rarely) 180. In this part of the disk dots, occa- 

 sionally running together into a complicated short tract, may be seen, not 

 specially conformed to the areolar structure, but in some places crossing it, 

 and elsewhere scattered about it. The number of short irregular discon- 

 tinuous lines which occur mixed with dots is very great ; none of them 

 appear to be regularly curved or regularly straight, but seem to be intervals 

 merely between more enlightened parts. It does not seem to me that dots 

 of greater darkness usually appear at the intersections or terminations of 

 these fissure-like objects. 



PI. XII. fig. 4, is intended to convey the impression arising from a close 

 study of one small space quite definite in character and marked by distinct 

 small dots, one elongated in the middle part of a subpentagonal space, 

 around which other less regular areolse were gathered. After much atten- 

 tion, it appeared to me that the boundaries of this rude pentagon were in 

 part broken up into irregular short loops and dots ; and though the obser- 

 vation was difficult, I am not afraid to trust it. This selected space is drawn 

 on a larger scale, but it was not seen with higher powers than No. 3. 



PI. XII. fig. 5 shows a curious areola with a black central dot, and three 

 parallel markings on the boundary. 



PI. XII. fig. 6, a sketch made in April 1864, is introduced for com- 

 parison, and especially for the softly luminous mottling of the surface. 



I shall be very glad to be informed whether what is here said agrees or not 

 with the observations of other persons, made with other instruments. 



