48 Prof. Loomis on the Hail Storm of the first of July, 1853. — 
minutes. Ina vacuum, a stone would fall from the height of | 
5000 feet in less than 20 seconds—but drops of water and hail — 
stones fall with only a moderate velocity. From my own ob- 
servations of the hail stones of July Ist, [ estimated the velocity 
f their fall at about 40 feet per second. At the uniform rate oj 
AO feet per second, a stone would be more than two minutes in 
falling 5000 feet. 
In order to obtain some reliable data for estimating the velocity 
of hail stones, I have computed the greatest velocity of a num- 
ber of small bodies differing in size and specific gravity. Dr 
Hutton determined by numerous experiments the resistance of 
the air to bodies moving with different velocities; and in the 
third volume of his Tracts, p. 218, has given a table of the air’s — 
resistance to a sphere 2 inches in diameter. His experiments also _ 
indicated that the resistance, of spheres increases in a ratio some- 
what greater than the squares of the diameters. This excess for 
numbers in the second column, and diminishing the result by 
one-thirtieth part. Hach succeeding column is derived from the 
preceding in a similar manner. 
Resistance of the air to Spheres of different Diameters. ee | 
Velocity |Sphere 2 inch- |\Sphere 1 inch (Sphere } inch {Sphere 4 inch |Sphere + inch 
per second es in diameter.| in diameter. | in diameter. | in diameter. , in diameter. 
feet ounces. ounces, ounces 
5 0-006 0-001 0:000 
10 0°026 0°006 0001 
15 0°058 0-014 0°0038 
20 0°108 0°025 0°006 
25 0163 0039 0'010 
30 0°237 0057 0-014 
35 0325 0-078 0019 
40 0427 0-103 0025 
45 0544 07131 0032 
50 0676 0163 0-039 
55 0°821 0-198 0-048 
60 0-981 0-237 0°057 
1155 0°279 0-067 
70 0°325 0:078 
45 1546 0374 0:090 
80 1-76 0426 0103 
85 1-996 0-482 0-116 
90 2°243 0542 0-131 
5 2°505 0°605 0146 
100 2°780 0672 07162 
200 11°340 27 0668 
300 25°800 6235 1:507 
