166 G. Jones on the Zodiacal Light. 
that the case required. It was a great satisfaction, after my Tfe- 
turn home, to find that Baron Humboldt had observed the same 
thing while in southern latitudes, though he thought it more 
probable that it was owing to “ processes of condensation going 
on in the uppermost strata of air, by means of which the trans- 
parency, or rather the reflection of light, may be modi i 
nner.” My records, however, 
quite dying away; and so back and forth for about three-q 
ters of an hour; and then a change still higher upwards, to 
more permanent bounds. 
A reference to the charts will show zigzag lines in some of 
them down near the horizon. These are the boundaries of a 
very effulgent light which appeared at the times specified, and 
within these bounds. It has no other distinction than its greater 
brightness, and the cause of it I cannot surmise. Cassini appears 
to have noticed the same thing as will be seen by reference to 
his annotations. 
Light, and in coloring, it was all the same; and, in its su 
oar rapid changes, it still kept strictly within the Zodiacal 
t bo The’ : : e 
records; and I never failed afterwards to watch for recurrences 
of such light. But they did not often present themselves; for 
