# File lib/rubygame/sound.rb, line 96
  def initialize( sound=nil )
    if( sound.instance_of? SDL::Mixer::Chunk )
      @struct  = sound
      @volume  = 1
      @channel = -1
    else
      raise( NotImplementedError, "Sound.new is not implemented. "+
             "Use Sound.load to load a sound file." )
    end
  end