380 Solar Eclipse of July, 1860. 



This cloud according to M. Villarceau, in two minutes time was 

 displaced 3^° on the moon's disc, in moving to the west. The 

 measurement of M. Chacornac's cover over an interval of six min- 

 utes in time, in which the cloud moved ll^°. 



Beautiful observation, and one which could not have been 

 hoped for ! We see that the duration of the motion studied by 

 Chacornac, much exceeds the time of total obscuration. The 

 last measure was made more than three minutes after sun-light 

 had reappeared ! It is important to note, among other points 

 that this was not done with a cloud vaguely seen after the return 

 of sun-light, but fortunately it was a measurement so carefully 

 made as to be a gurantee against the possibility of illusion. It 

 should be added that the displacement of the luminous cloud de- 

 termined by observations made at the Sanctuaire, is precisely, 

 equal to that required by calculation, assuming the cloud to belong 

 to the sun. There remains, then, no foundation for a doubt, as 

 to the nature of the rosy clouds which have been variously called 

 flames, mountains, protuberences, and clouds. 



The observation on one of the appendages, perfectly isolated 

 from the disc of both sun and moon and of a sharply pronounced 

 character, and on the other the appearance of a rosy band on the 

 west at the moment of emersion, and the rate of motion of a second 

 appendage, fixed by Villarceau and Chacornac, prove that these 

 objects belong to the sun. Let us then hereafter give the name 

 of solar clouds to the rosy appendages which become visible when 

 the solar light is sufficiently dimmed. 



A few words more will finish the description of the phenome- 

 non and of the observatians. Ismail EfFendi, a young Egyptian 

 attached to the Paiis observatory for three years past, a very ex- 

 pert astronomer, and who accompanied the French expedition to 

 Spain, has sent me a drawing which proves the appearance of lu- 

 minous clouds in the east immediately before the commencement 

 of the eclipse. The clouds in question form a slightly elevated but 

 continuous band embracing 95° of the outline of the sun. This 

 band w^as not long visible, but was eclipsed behind the lunar disc, 

 and it had in efi'ect ceased when I passed over this region in ex- 

 ploring the whole periphery with a power which allowed me to 

 see only portions successively. 



The magnetic observations were made at Paris, the variations 

 being sensibly simultaneous for the whole of Europe, and M. 

 Desains, who took note of the magnetic observations, detected no 

 perturbations during the eclipse. 



