Ucke, Christian; Schlichting, Hans-Joachim (1995). "Der Kaffeekugelschreiber oder das Liebesthermometer" [The coffee-percolator pen or the love thermometer]. Physik in unserer Zeit (in German). 26 (4): 192–193. Bibcode:1995PhuZ...26..192U. doi:10.1002/piuz.19950260412.
Ucke, Christian; Schlichting, Hans-Joachim (1995). "Der Kaffeekugelschreiber oder das Liebesthermometer" [The coffee-percolator pen or the love thermometer]. Physik in unserer Zeit (in German). 26 (4): 192–193. Bibcode:1995PhuZ...26..192U. doi:10.1002/piuz.19950260412.
The Franklin tube or pulse hammer differed in form from the water hammer. The pulse hammer (German: Pulshammer) and the water hammer (German: Wasserhammer) are illustrated in: Frick, Joseph; Lehman, Otto (1905). Physikalische Technik oder Anleitung zu Experimentalvorträgen[Physics equipment or manual of lecture demonstrations] (in German). Vol.1, part 2 (7thed.). Braunschweig, Germany: Friedrich Vieweg & Sohn. p.1084. The Franklin tube or pulse hammer is illustrated by Fig. 2916; the water hammer is illustrated by Fig. 2917.