TRANSACTIONS OF THE SECTIONS. 35 
gress,—and proves that the velocity with which a sound is transmitted through the 
atmosphere depends on the degree of violence with which it was produced, and not 
(as in light) on the length of the wave; so that sounds of every pitch will travel at 
the same rate, if their genesis do not differ much in violence ; but a violent sound, 
as the report of fire-arms, will travel sensibly faster than a gentle sound, such as the 
human voice. This last property the author stated to have caused him much trouble, 
in consequence of its being directly opposed to the testimony of almost every expe- 
rimenter. For many affirmed, as the direct result of their observations, and others 
assumed, that all sounds travel at the same rate, Fortunately, it transpired at the 
Meeting, that in Captain Parry’s Expedition to the North, whilst making experiments 
on sound, during which it was necessary to fire a cannon at the word of command 
given by an officer, it was found that the persons stationed at the distance of three 
miles to mark the arrival of the report of the gun, always heard the report of the 
gun before they heard the command to fire; thus proving that the sound of the gun’s 
report had outstripped the sound of the officer’s voice; and confirming in a remarkable 
manner the result of the author’s mathematical investigations, that the velocity of 
sound depends in some degree on its intensity. 
METEOROLOGY. 
On the Formation of Hail, as illustrated by Local Storms. 
By W. R. Bownitcu, B.A. 
With the fourth or fifth flash of lightning fell hailstones which averaged from half 
an inch to an inch in diameter. These hailstones accompanied every flash, which 
appeared to come from the zenith to the place where I was standing; but as soon as 
the storm had passed away so far that the interval between the flash and report was 
appreciable, the hail either did not reach us, or but a very few hailstones fell mingled 
with heavy rain. Between the flashes rain only fell: with the flash came a volley of 
hailstones, and gradually a few drops of rain would mingle with the hail, until at 
length rain only was falling. The transition from rain to hail was sharp and well- 
defined; that from hail to rain very gradual. 
* The hailstones which fell were of three kinds :— 
_ I. Solid balls of ice having two or three small bubbles, or one larger one contain- 
ing air. 
II. Balls of which from half te two-thirds consisted of solid ice, the remainder 
being water and air enclosed in a crust of ice. 
Ill. Balls formed of an outer crust of ice containing water and air. In some 
instances this icy crust was so thin as to be broken by the fall (though all which I 
examined fell upon straw), while in others it was thicker, and bore considerable 
pressure before it broke. 
In form the hailstones were spheroidal, sensibly bulged at the part corresponding 
to the equator on a globe, and depressed at the parts corresponding to the two tro- 
pics and the arctic and antarctic circles; and in many, if not all, cases slightly 
elevated at the two poles. My attention was specially directed to this latter point, 
and although in some instances the elevation (if any) was insufficient to warrant a 
judgment without measurement, in many no doubt whatever could be entertained, 
for the polar portion was evidently tending to form a point. It appeared as if the 
drop had been originally a perfect sphere, which, by rotation on its own axis had 
become formed as found, and had then suffered congelation. The bulging towards 
the equator, and the elevation at the poles appeared the complements of the depres- 
sions above described. 
The regularity and perfection of form of these bodies forbid the notion of gradual 
accretion in their descent, aud put beyond question the fact of their form being due 
to the action of a natural law upon fluid bodies placed in the same circumstances: 
It is to be hoped that other observations, or direct experiments, may enable us to 
ascertain whether this is the normal form of drops of water falling freely and rapidly 
= g* 
