the Nature of the Sun . 279 
distance from the shallows to the opaque surface should be 
considerable. 
I have compared the darkness of two openings near the 
centre, with the appearance of that near the preceding limb. 
It is decidedly in favour of the blackness of the latter : this is 
however larger than the former two; which may occasion 
deceptions. 
The opening near the limb is certainly darker than the two 
which are near the centre. 
Feb. 5, 1801. An opening very near the preceding margin is 
of a deep black colour ; certainly more so than another which is 
not far off, but is more towards the centre of the sun. 
Feb. 8, 1801. The large opening near the margin, is darker 
than two other openings which are about the centre of the solar 
disk : the difference, however, is hardly sufficient to be decisive. 
The two openings are also much smaller; which may occasion 
a deception. 
Distance between the Shallows and solar Surface , indicated by the 
free Motion of low Clouds. 
Jan. 25, 1801. 9 h 22'. A large opening, which I have been 
observing since the 19th, is now much advanced towards the 
limb.* I can see into it; and, on the preceding side, as it ap- 
pears to me, a good way under the lowest regions of the clouds 
of which the shallow consists. The upper margin of the shal- 
low is very sharply determined ; but the clouds of the lower part 
of it, on the contrary, are more dispersed ; some of them hanging 
a good way down, towards the surface of the sun’s body.-f 
io h 20 / . The preceding side of the shallow of the large 
* See Plate XIX. Fig. 10. + See Fig. u. 
