D. Kirkwood on the Meteoric Fireball of July, 1846. 347 
It may be considered as established that the migrations of birds 
are generally more or less in a north and south direction, influ- 
enced very materially by river courses, mountain chains, forests, 
Conditions of moisture, mean temperature, altitude, ete. Mid- 
dendorf (Die Isepiptesen Russlands) suggests that birds migrate 
in the direction of the magnetic pole; a suggestion not at all 
ca, 
It may be further remarked that while birds ee 
y a definite 
tes in either spring or autumn, and are not known there in the 
other season. This is a fact well known to the diligent collector, 
and I have been inclined to think that, in very many instances, 
birds proceed northward along the valley of the Mississippi, to 
Teturn along the coast of *the Atlantic. : 
In general the northward vernal movement is performed 
much more rapidly, and with fewer stops by the way, than the 
autumnal. i 
Birds generally make their appearance in given localities 
with wonderful regularity in the spring, the Sylvicolide espe- 
cially; a difference of a few days in successive years attracting 
the notice of the careful observer; this difference is generally in- 
uenced by the season. The time of autumnal return 1s, per- 
haps, less definite. 
Arr. XLII—On the Meteoric Fireball of July 18th, 1846; by 
DanieL Kirxwoop, LL.D., Prof. of Math., Indiana State 
University. 
ON the 13th of July, 1846, at about 9h. 30m. P. a, a brilliant 
fireball passed over Maryland and Pennsylvania, and was seen 
also in Virginia, Delaware, New Jersey, New York and Con- 
hecticut. This meteor was noticed in many newspapers imme- 
diately after its appearance; but I believe no account of it was 
given in this Journal. i 
When this brilliant object appeared I was in the parlor of a 
friend, in York, Pennsylvania. The meteoric light shone bright- 
ly into the room, and immediately after, I heard exclamations of 
Surprise from persons in the street. I hurried to the door, but 
fore I could reach a point from which the meteor was wisible 
it had disappeared. The same evening, and also the next day, 
Several citizens of York, who had had Sst he de of oe aa 
Or, pointed out, at my request, its apparent path. 
subsequently Thad petloas in Chanceford, York Co., Pa. (twenty- 
