134 Remarks on Atmospheric Dust. 
There was also, two years before, a fall of hail in the 
same county, which was to me in some respects new.— 
The hail stones were generally about one fourth or three 
eighths of an inch thick and of sufficient dimension in length 
and breadth to hide a shilling, and in many cases a cent, and 
almost every one perforated in the middle as if they had 
been held between the fingers, till the fingers by their 
. warmth had melted away the middle and had met. When 
the perforation was not complete, there was in every case 
an inclination to perforation. The storm was tremendous, 
but of short duration and took place in the heat of summer. 
I observed then and have many times observed since, 
that hail. is usually accompanied by contrary winds which 
seem striving over our heads for the mastery. I wish sir, 
to ask you, is not the hail always produced by conflicting 
winds, which, in the place where they meet, force the at- 
mosphere above the freezing point, and cause the vapour 
to congeal? And if this be the fact will not the hail be lar- 
ger or ‘smaller as in proportion to the strength of the conten- 
ding tempests ? When the winds are strong will not the 
hail rise during the first periods of its formation, and con- 
tinue to rise while the stream of atmosphere which is set- 
ting upward can support its weight, and thus be kept the 
longer time above the freezing point and become so much 
ihe larger. The perforation in the case above mentioned 
was, I suppose, effected while falling, but by what means 
{ know not. The hail might have been strung like so many 
beads. 
Arr. XV. Remarks on Atmospheric Dust, in reply to Mr. 
RaFiINESsQueE. 
TO PROFESSOR SILLIMAN. 
Sir, 
BEING a subscriber to your Journal, I observe, (Vol. L. 
No. IV. p. 397,) an article from the ingenious and learned 
Mr. Rafinesque, on Atmospheric Dust. I confess I can 
hardly agree with that gentleman in several opinions which 
