The test method is based on the fact that defective (faulty) glass containers are destroyed by the effect of ultrasound, while mechanically perfect containers remain undamaged. The containers are guided successively in a liquid bath past an ultrasonic horn. In this process, the ultrasonic power and the distance of the containers from the ultrasonic horn are dimensioned such that the containers floating freely in the region of the ultrasonic horn are sucked in by the underpressure (subatmospheric pressure) which prevails in the liquid bath below the ultrasonic horn. <IMAGE>
