inous travelers.
Minerva's hasty flight from the peaks of Olympus to break the truce
between the Greeks and Trojans, is compared by Homer to the emission of
a brilliant star. Virgil, in the first book of the Georgics, mentions
the shooting stars as prognosticating weather changes:

"And on, before tempestuous winds arise,
The seeming stars fall headlong from the skies,
And, shooting through the darkness, gild the night
With sweeping glories and long trains of light."

Various hypotheses have been framed to explain the nature and origin of
these remarkable appearances. When electricity began to be understood,
this was thought to afford a satisfactory explanation, and the shooting
stars were regarded by Beccaria and Vassali as merely electrical sparks.
When the inflammable nature of the gases became known, Lavosier and
Volta supposed an accumulation of hydrogen in the higher regions of the
atmosphere, because of its inferior density, giving rise by ignition to
the meteoric exhibitions. While these theories of the older philosophers
have been shown to be untenable, there is still great obscurity resting
upon the question, though we have reason to refer the phenomena to a
cause exterior to the bounds of our atmosphere. Upon this ground, the
subject assumes a strictly astronomical aspect, and claims a place in a
treatise on the economy of the solar system.

The first attempt accurately to investigate these elegant meteors was
made by two university students, afterward Professors Brandes of
Leipsic, and Benzenberg of Dusseldorf, in the year 1798. They selected a
base line of 46,200 feet, somewhat less than nine English miles, and
placed themselves at its extremities on appointed nights, for the
purpose of ascertaining their average altitude and velocity. Out of
twenty-two appearances identified as the same, they found,

7 under 45 miles
9 between 45 and 90 miles
5 above 90 miles
1 above 140 miles.

The greatest observed velocity gave twenty-five miles in a second. A
more extensive plan was organized by Brandes in the year 1823, and
carried into effect in the neighborhood of Breslaw. Out of ninety-eight
appearances, the computed heights were,

4 under 15 miles
15 from 15 to 30 miles
22 from 30 to 45 miles
33 from 45 to 70 miles
13 from 70 to 90 miles
6 above 90 miles
5 from 140 to 460 miles.

The velocities were between eighteen and thirty-six miles in a second,
an averag