OF A METEORIC FIRE-BALL. 33
signature “ G. G.,” in which the writer, who was on a visit here from his residence
at No. 216 Walnut street, Philadelphia, thus describes the phenomena:—
“ A large ball of fire of intense brilliancy appeared in the sky, at an apparent
height of from twenty to twenty-five degrees above the horizon, a little to the north
of a due west direction, moving to the east. It was at first partially obscured by
the light clouds, from which in a few moments it emerged. In size it appeared
from eight to twelve inches in diameter. Its color was that of the most pure and
white flame. Its movement was so comparatively slow and regular that the idea
occurred to us both, while looking at it, that it might be an artificial contrivance
sent up from Fort Mifflin or the Gas Works, by some experimenter in rockets or
balloon fire works. It appeared to be between us and the city. It quickly sepa
rated into two balls of similar appearance, one closely following the other. These
again soon began to throw out, at first a trail of their own white appearance, and
quickly after, large, distinct, and numerous fragments of the most beautiful red and
pink colors, the effect being like that of the bursting of an ordinary rocket, only
on a scale much more magnificent and grand. This continued gradually dimin
ishing until the meteor, which now had assumed a red hue, had reached a point
nearly due east, where it disappeared from our view at a height apparently nearly
the same as that at which it started.
“ The movement of this meteor appeared to be not much more rapid than the
flight of an eagle. I think I could have kept sight on it easily with a gun through
out its course. The length of time we enjoyed this wonderful sight, it seems to
me, must have been considerably more than a minute. The ladies and children
had retired, but they all had time to go to the windows, in response to our calls,
and witness it.”
Wrentham , Massachusetts, Lat. 42° 1', Lon. 71° 23'. Reported time “ about 10
o’clock.” 1
Whatever may have been the orbit of the meteor before it became visible, it is
obvious that the portion of the path that was subject to observation, being so near
the earth, must have been controlled almost entirely by its attraction—that of the
sun, or of the other planets, exerting so little disturbing influence as scarcely to be
appreciable. The orbit about to be described is not, therefore, the path of the
meteor in space, but only its orbit relative to the earth, and having the centre of
the earth in one of its foci, according to well-known principles.
A phenomenon of this kind being unexpected, and therefore not admitting of
previous preparation on the part of observers, it was not supposed, when the inves
tigation was commenced, that the observations were accurate enough to warrant
any very refined analysis, and I proceeded to determine the path upon the assump
tion that the earth was a sphere, 7912 miles in diameter, and so did not take into
account its spheroidal form, nor the difference between the true and the apparent
zenith. The error was an unfortunate one, and has, in some degree, vitiated the
results; but I shrink from the labor of cancelling all that has been done, and begin-
1 Calculated time of meridian passage at Wrentham 9h. 58m. 39 sec.
5 April, 1869.