144 Miscellaneous Intelligence. 
With reference to the relation between the column and the arches, | 
have shown, in discussing our observations on partial corona, that even 
when the rays appear isolated and independent, they have a general 
arrangement in files or ranges, parallel to the direction of the arches. 
I have also shown a tendency in the arches to dissolve into columns 3; 
whence it is obvious that the simple ray is the result of an arrange- 
ment of the auroral light in lines parallel to the dipping needle. The 
arched form results from this, that if two rays exist simultaneously, 
they tend to place themselves so that their common place shall be per- 
pendicular to the magnetic meridian, as if the equilibrium of two rays 
were not stable except in this position. But how this condition of sta- 
bility is consistent with the idea that the rays have an electric nature 
and origin, is yet enveloped in mystery. 
The luminous currents, exhibited in the ranges of columns, passing 
either from the east to the west or the reverse, are not equally frequent 
in the different directions; the same remark applies to the modes of 
progression in the arches from the north to the south and from the 
south to the north. I state the facts on this subject without pretending 
to offer any explanation. 
"We have observed the extra-zenith corona so frequently, as to be 
able to affirm that the coronas may appear in all possible directions in 
relation to the observer, and that their connection with the magnetic 
zenith is a simple result of linear perspective. : 
In the fourth paragraph I have treated of the auroral sheets. They 
are allied to the rays, but differ in their flickering or palpitating light 
and also in appearing only at a later hour of the night. 
paragraph relates to the colors of the auroral light, which 
are less varied than generally supposed; for but three or four distinct 
shades were observed by us. 
In the sixth paragraph I consider the facts which may lead the ob- 
server to suppose that the aurora is situated but a small distance from 
though believing that their appearances are mostly deceptive, 
donot affirm that all observations of this kind hitherto made are ne- 
cessarily incorrect. I next treat of a resemblance, between the mean 
orientation of cirro-cumuli clouds in parallel bands optically convergent, 
a more precise determination. For such investigations, the base line 
should be about 100 kilometers long (60 miles), and in the direction 
of a terrestrial magnetic meridian. 
The last paragraph contains general remarks on the frequency of 
the phenomena, its duration, hour of appearance, its possible continu- 
ance during a succession of days. I show that the progressive move- 
ments of the arches are wholly independent of the motion of the earth, 
which sets aside any theory founded on the idea of the cosmical origin 
of the Aurora, and sustains the view that it belongs to our atmosphere 
