202 FRAGMENTS OF SCIENCE. 
The whole of the observations here referred to were em- 
braced by an angle of about 70 degrees, of which 50 
degrees lay on the one side and 20 degrees on the other side 
of the line of fire. The shots were heard by eleven observers 
on board the Galatea, which took up positions varying 
from 2 miles to 13^ miles from the firing-point. In all 
these observations the reinforcing action of the reflector, 
and of the parabolic muzzle of the gun, came into play. 
But the reinforcement of the sound in one direction 
implies its withdrawal from some other direction, 
and accordingly it was found that at a distance of 5 
miles from the firing-point, and on a line including nearly 
an angle of 90 degrees with the line of fire, the gun-cotton 
in the open beat the new gun; while behind the station, 
at distances of 8 miles and 13- miles respectively, the gun- 
cotton in the open beat both the gun and the gun-cotton 
in the reflector. This result is rendered more important 
by the fact that the sound reached the Mucking Light, a 
distance of 13 miles, against a light wind nhich was 
blowing at the time. 
Most, if not all, of our ordinary sound-producers send 
forth waves which are not of uniform intensity through- 
out. A trumpet is loudest in the direction of its axis. 
The same is true of a gun. A bell, with its mouth pointed 
upward or downward, sends forth waves which are far 
denser in the horizontal plane passing through the bell 
than at an angular distance of 90 degrees from that plane. 
The oldest bellhangers must have been aware of the fact 
that the sides of the bell, and not its mouth, emitted the 
strongest sound, their practice being probably determined 
by this knowledge. Our slabs of gun-cotton also emit 
waves of different densities in different parts. It has 
occurred in the experiments at Shoeburyness that when 
the broad side of a slab was turned toward the suspending 
wire of a second slab six feet distant, the wire was cut by 
the explosion, while when the edge of the slab was turned 
to the wire this never occurred. To the circumstance that 
the broadsides of the slabs faced the sea is probably to be 
ascribed the remarkable fact observed on March 23d, that 
in two directions, not far removed from the line of fire, the 
gun-cotton detonated in the open had a slight advantage 
over the new gun. 
Theoretic considerations rendered it probable that the 
