1865.] 



Astronomy. 



443 



in which the reflecting surface makes an angle of 45° both in the inci- 

 dent ray and the axis of the eye-piece, and the second surface is at 

 right angles with the transmitted pencil. With it observations may 

 be made with comfort and ease, even for a very long time, without 

 any fatigue to the eye, although with the full aperture. An examina- 

 tion of one very large spot gave Father Secchi a very good sight of 

 the so-called willow-leaves. He observes that there is not in any 

 place any uniform tint, but an agglomeration of oblong and white 

 bodies, having one-third or one-fourth of a second of arc in breadth, 

 and of very different lengths. It is very difficult to compare them to 

 any terrestrial object, but the name of leaves is not very badly chosen. 

 The accompanying woodcut, which has been copied by the kind per- 



mission of Mr. De la Eue, gives some idea of the appearance of this 

 spot, although the writer thicks that it is quite impossible to delineate 

 it as it really appeared. What is very singular is, that these white 

 bodies in some places agglomerate together so thickly that they con- 

 stitute a continuing stream, but in general they are broken. These 

 bodies are more apparent and separated when the spot is very enlarged, 

 as it is in the present case. The general body of the sun is also made 

 up of these oblong bodies, but of every form and dimension. A 

 great many black pores seem to show that the photospbere is not a 

 continuous stratum, but at the first sight it appears made of little 



