160 On the Meteors of 13th November, 1833. 
The only remaining supposition is, that the matter of which the 
denser parts of the cloud was composed, (the parts which were dis- 
sipated without actual combustion) after having having been subject- 
ed to so powerful a degree of incandescence, remained luminous 
for a while after the combustion had ceased. ‘This is a well known 
consequence of the exposure of various substances to a very intense 
light. Thus, after passing the electric spark from a large Leyden 
jar, through fluor spar, the mineral remains luminous for several min- 
utes. It must be considered, also, that only a very small portion of 
light is required to render a body slightly luminous in the dark. 
So great a number of bodies, some of which it appears, were very 
large, falling nearly through the atmosphere with so prodigious 
a velocity, must have produced extensive derangements, an the at- 
mospheric currents. ‘The first effect was a westerly wind, whieh 
suddenly succeeded the meteoric shower, in nearly every place where 
the shower prevailed. (See p. 385.) A westerly wind (as appears 
from the testimony of Sir H. Davy, already recited) commonly fol- 
lows this phenomenon. Large volumes of air suddenly driven from 
the upper to the lower regions of the atmosphere, must have a rela- 
tive motion eastward, since the velocity due to their greater distance 
from the earth, derived from the diurnal revolution, would not be 
instantly lost on their descending to a lower level. In our latitude, 
(41° 18’) a body of air descending suddenly to the surface of the 
earth from the height of twenty miles would have a relative velocity 
eastward of five miles per hour. For, the cosine of the latitude 
being 2972 miles, and the diurnal motion 750 miles an_ hour, 
2972 : 2992::750 : 755=the velocity at the elevation of 20 miles. 
A second consequence was, a sudden production of cold, an effect 
which would follow of course from the descent of such large quan- 
tities of air from the regions of perpetual frost.* A third consequence 
would be the destruction of the equilibrium of the atmosphere, and 
the prevalence of gales in various parts of the ocean. Nor is it al- 
together improbable that some change of seasons should result from 
so extensive a disturbance of the atmospheric equilibrium, and there- 
fore that the remarkably warm weather of the northwestern parts of 
the United States as described by Mr. Schoolcraft, may have been 
* The heat extricated by condensation might be supposed an equivalent; but this, 
when produced by sudden compression would not heat a gaseous medium, which is 
the worst of all conductors of caloric, but would escape by radiation. 
