i 
180 Remarks on a Curious Effect of Solar Light.” 
completed, will be the standard book of reference for the bota- 
nists of the northern and middle states. This compendium, 
which is after the model of Smith’s Compendium Flore Britan- 
nice, containing the tial generic and specific characters of 
all the plants described in the Jarger Flora, with the habitat, 
time of flowering, &e. of each plant, will be a convenient 
manual for the travelling botanist, and will be almost indis- 
pensable to the student of botany who is not in possession of 
the author’s larger Flora. . 
XXVIII. Remarks on a“ Curious Effect of Svlar Light,” 
p- 164—in a note to the Editor.—Since the communication 
on page 164 was struck off, | have read an account of a 
similar appearance in the Isle of Wight, in the Journal of the 
Royal Institution, "The writer of that article supposes it to 
have been an effect of perspective, and that it was caused by 
clouds below the western horizon, and therefore not visible to 
the spectator—(it occurred after sun-set). In both cases ob- 
served by me, it occurred before sun-set.—In the first instance, 
the sky was perfectly clear, except the bank of clouds in the 
N_ E.—I do not recollect a single cloud in the rest of the 
hemisphere, and my attention was attracted by the extraordi- 
mary clearness of the sky. The air had that dense transpa- 
rency, (if I may so express myself,) which sometimes pre- 
