ON THE 
ORBIT AND PHENOMENA OF A METEORIC FIRE-BALL, 
WHICH PASSED OYER PORTIONS OF THE UNITED STATES AND CANADA, ON THE 20TH OF JULY, 1860. 
On the evening of July 20th, 1860, a meteoric fire-ball passed over the northern 
parts of the United States and the adjacent parts of Canada, of so extraordinary 
brilliancy as to attract the attention of numerous observers along its entire visible 
track of nearly or quite 1300 miles, and on either side of it to the distance of 
several hundred miles. It was reported to have been first seen moving eastward 
from a point nearly over the western shore of Lake Michigan, though it not improb 
ably became luminous when it was somewhat further west, as the sky over all that 
region was obscured by clouds, and it was not till the meteor had reached a point 
some 150 miles further east that the first reliable determination of its position was 
made. From thence many eyes watched its course till it disappeared quite out at 
sea in a southeasterly direction from the island of Nantucket. 
From the following series of observations, obtained partly from the newspapers 
of the time, partly through the co-operation of scientific friends, who, at the request 
of the writer, kindly made inquiries in regard to the phenomenon in their respective 
localities, or measurements of the meteor’s position, as estimated by themselves or 
pointed out by those who saw it; and partly from collections kindly put into his 
hands for the purpose by the Smithsonian Institution, and by Profs. Lyman and 
Newton, of Yale College, an attempt has been made to determine the elements of 
its orbit or path. * 1 At a few of the places, where estimates of the meteor’s altitude 
at special azimuths were desired, and where the proper instruments for this mea 
surement were not at hand, estimates were made by a sort of extemporized quad 
rant in the following manner, -which, for the sake of brevity, is designated in the 
following series as the “ card method.” From a point in a line drawn upon a card 
(or sheet of paper attached to a piece of board), a small weight was suspended by a 
string, and the card being held in a vertical position, and the line directed toward 
the estimated place of the meteor, when it was at the specified azimuth, the position 
of the string was noted, as it rested against the card, and a line drawn upon the 
1 In making the computations, valuable aid was contributed by Mr. Benjamin F. Stem, A. M., a 
gentleman of superior mathematical attainments ; by my son, Selden J. Coffin, A.M., and by Messrs. 
W. P. Montelius and A. P. Reid, members of the Senior Class in Lafayette College. 
1 January, 1869. / 1 \