192 Researches on Solar Physics. 
spots observed by Carrington. Again, we have seen (Art. 26) 
that the faculs fall behind; so that we may imagine two cur- 
rents to be engaged in the formation of a spot,—the one an as- 
cending current carrying the hot matter behind, the other a de- 
scending current carrying the cold matter forward. One advan- 
tage of this explanation is that all the gradations of darkness, 
from the faculze to the central umbra, are thus supposed to be 
due to the same cause—namely, the presence to a greater or less 
extent of a comparatively cold absorbing atmosphere. 
81. It is but just to ourselves and to M. Faye, to mention that 
both have imagined the phenomenon of sun-spots to be due to 
ascending a escending currents. M. Faye’s hypothesis was 
published a little before ours; but we shall readily be believed 
when we state that an idea of this kind presided over the con- 
32. In conclusion, we would venture to suggest that if the 
photosphere of the sun be the plane of condensation of gaseous 
hat at the epoch of minimum spot-frequency this plane is up 
lifted very high in the solar atmosphere, so that there is com 
selves with suggesting this to the observers of our luminary 4 
a simple inquiry that may possibly prove productive. é 
33, We are especially desirous of bringing under the early 
notice of the scientific world the aceumulation of observations 
conjectures in elucidation of solar 2 eens In venturing _ 
