284 Tornado in N. E. part of Ohio, Feb. 4, 1842. 
from a gun of two inches calibre into solid blocks of elm wood; 
in the direction of the fibres, penetrated the following distances: 
With a charge of 2 oz. powder, velocity 800 feet per second, penetration 7 inches. 
. ce 4 74 1200 és 15 thstig 
; st 8 “ 1600 “ 90) $5 
Dr. Hutton estimates the resistance of elm timber 7} times more 
than that of firm earth. A pound ball with a velocity of 800 
feet should then penetrate the earth 51 inches. 'The depth pen+- 
etrated being assumed to be as the square of the velocity, a pound 
ball fired with the velocity of 550 feet would penetrate 24 inches. 
The space penetrated is said to be as the specific gravity of the 
ball. A wooden ball two inches in diameter, specific gravity .75, 
fired with a velocity of 550 feet should then penetrate firm earth 
2.4 inches. As this last result is a deduction from principles 
somewhat doubtful, I desired to verify it by experiments of my 
own. A six pounder was accordingly charged with 1} pounds 
of powder. ‘'T'wo or three short pieces of oak board, three inches 
wide and one inch thick, were added, and the gun pointed towards 
a steep hill distant about a rod. The boards penetrated the ground 
a few inches, were badly shivered and bounded some distance Up 
the hill. A second experiment was tried with nearly the same 
result. The hill was of usually firm earth but not stony. The 
greatest penetration did not exceed six inches. Velocity cour 
puted 1000 feet per second. According to the former data, the 
penetration should have been nearly eight inches. But the ground 
at Mayfield was saturated with water. I have no precise data for 
estimating the allowance required by this circumstance. I judge 
however that it would not increase the penetration more than 
threefold. We arrive then at the conclusion that the clap-boards 
at Mayfield were driven into the earth with a velocity of 1000 
feet per second or 682 miles per hour. 
Ido not by any means suppose that the velocity was the same 
throughout the entire track. On the southeast half, probably the 
velocity did not exceed three times the ——* motion of the 
tornado. — 
Let we iacow determine the directions of the wind. For ‘this 
rpose v he bearings of about seventy prostrate trees 
xt a dit ; Across the qn in the direction N O. We did not 
‘empt to measure ‘the. bearings of all at. inulin ae 
eer »peless task ae 
le i eae. a 
