Aufnahmen aus den Jahren 1942/43, hergestellt mit der funkenkinematographischen Methode nach Cranz und Schardin als Dokumentation des 1939 erreichten Kenntnisstandes vom spröden Bruchvorgang. Erstmalige Berechnung der maximalen Bruchgeschwindigkeit in technischen Gläsern zu 1520 m/sec.

Historically valuable cinematographic shots of crack propagation in various industrial glasses. The shots were taken using the spark cinematographic method developed in the years 1942/43 by Carl Cranz and Hubert Schardin. Together with the unaltered text of the original accompanying publication, they are proof of the high level of knowledge of brittle fracture gained in the years 1937 to 1939. From these shots it was possible for the first time to calculate the maximum rate of fracture in plate and mirror glass as being 1520 metres per second.