350 D. Kirkwood on the Meteoric Fireball of July, 1846. 
rent altitude at disappearance being about 72°, would give its 
elevation above the earth’s surface about 18 miles. It was a lit- 
tle northeast of Lebanon, Penn., when first seen at New Haven, 
and its distance from the latter was about 189 miles. The cor- 
responding altitude was 33 miles; or if we suppose this angle 
of elevation to have been 18° (and the writer admits an uncer- 
tainty of two or three degrees) the altitude was 44 miles. 
When nearest York its altitude, according to Mr. Ettinger’s 
estimate of the zenith distance, was about 68 miles; and when 
nearest Gettysburg, (the zenith distance being 25°), about 70 
miles. The point in Virginia to which it was vertical when 
first seen froin Gettysburg was probably about 50 miles south- 
west of Washington, D. C. The length of the projection of its 
visible path on the earth’s surface was therefore at least 250 
miles. The length of that portion observed from New Haven 
was about 78 miles. When it is remembered that the Gettys- 
miles. 
Velocity.—The estimates of the time of flight by different ob- 
servers were so discordant that nothing definite could be inferred 
from them. That of the observer at New Haven was perhaps 
the most reliable. This would give a velocity with reference to 
the earth’s surface of about four miles per second. The heliocen- 
tric velocity was probably between 20 and 25 miles per secon¢. 
Apparent magnitude.—The estimates of the apparent diameter 
by persons in York and Lancaster varied from + to # that of 
the fullmoon; whilesome at greater distances from the meteors 
Bern snag it about 3. The apparent size at New Haven was 
muc 
was much greater. Moreover, at York and Lancaster the 
meteor had a train about 1° in length, while nothing of the 
kind was observed at New Haven. 
was assured by persons in Harford count , Maryland, Chance- 
oaks that shortly after 
ie disappearance of the meteor a distinct report like that of @ 
distant cannon was heard. As this was noticed by a consider- 
able number of persons, and in plac 
other it is scarcely possible they could have been mistaken. AS 
might be expected, their estimates of the interval which elapsed 
were different; but Mr. Ettinger of York, who was paying pat- 
