Tyndall and Knoblauch maintained a correspondence on and off over the next 25 years .
Knoblauch 's student and collaborator on the diamagnetism work was John Tyndall .
John Tyndall and Knoblauch maintained a correspondence on and off over the next 25 years .
Knoblauch 's student and collaborator on the diamagnetism work was John Tyndall .