"You didn't hear the beam itself, since that's ultrasonic.
"The Wailing Octopus"
Harold Leland Goodwin
It had no effect whatever on any material structure and could be used inside an activated conveyer without deranging the conductor-mesh, as, say, a bullet or the vibration of an ultrasonic paralyzer would do, and it was instantly fatal to anything having a central nervous system.
"Time Crime"
H. Beam Piper
From it projected the barrels of two kinds of weapons-explosive and ultrasonic.
"Rip Foster in Ride the Gray Planet"
Harold Leland Goodwin