GUNFIRE NOISE

Pahiatua Herald, Volume XLXI, Issue 15163, 2 October 1942, Page 4

GUNFIRE NOISE

INJURY TO HEARING SMALL CALIBRE WORSE Interesting investigations on the effects on the auditory organs of cannon and other shooting, performed at the acoustics’ section of the Carolinian Hospital in Stockholm, were recently described in Swedish papers. Thousands of Swedish soldiers have had their hearing affected by the shooting during military practices. The physicians of the Carolinian Hospital studying the damages have found that small guns—air defence and other small calibre arms—injure the hearing more by their barking sound than the boom of heavy guns. Shooting with machineguns in a bunker may be adduced as an example. A fusillade of 10 to 15 minutes’ duration is quite sufficient to muddle the shooter so completely as to deprive him of the power to aim. It has even happened that shooting under such conditions has resulted in something like a concussion of the brain. The doctors do not consider this surprising, however, as it is known that the sound may rise 50 times above the painful stage. Nevertheless, a period of rest for the ear'is in most cases enough for restoration, and by using ear protection the effects can largely be avoided.

The equipment of the institute, which is housed in an absolutely silent room, includes a training machine for ‘‘air listeners.” During the past year a very comprehensive investigation has been conducted in Sweden for ascertaining tli© qualifications of air observers, which has proved well warranted. Quite a number of persons who are absolutely unsuitable for this important duty hav© been discovered by means of tests with this machine. The customary hearing examination through whispering is really ripe for rejection, according to the opinions of the doctors of the institute, as it is quite possible for a person to be deaf in respect of an important sound or tone, but not in the range for whispering.