the French Astronomical Expedition. 311 
its movement? or does each cloud remain invariably above the same 
he origin of the luminous 
e 
_ _willregularly, at the rate of a half second of are in a second of time, 
at 
should appear by the variation in height between those which appear in 
the east and the west. The phenomena will appear otherwise if the clouds 
n 
The height of these. clouds ought not to vary, it is true, whether 
ey be ong to the moon, or to the sun, but in the latter case, carried 
clouds, whether east and west or north and south, has the highest interest, 
the retur it was a measurement so care- 
a of sunlight, but fortunatel It should 
by caleulati ! the 
ation, assuming the cloud to belong to 
1 DO foundation for a doubt, as to the nature of the rosy clouds 
welch have been variously called flames, mountains, protuberances, and 
ouds, 
The observati appendages, perfectly iso 
dise of both <a ng ok — pi fe" pases pronounced character, 
on the other the appearance of a rosy band on the west at the = 
et emersion, and the rate of motion of a second appendage, fixe 
by Villarceau and Chacornac, prove that these objects belong to the Sun. 
