Small box labelled ‘Gelatine-Emulsionsplatten, J Gädicke, Berlin’, containing six glass slides relating to Hermann von Helmholtz [1821-94, German physician and physicist], being images of him and his scientific equipment. [Presumed to have been used to illustrate a Cambridge Philosophical Society lecture or article?]
The slides are numbered 1-6 and the box contains a handwritten list:
1. Helmholtz 27 years old;
2. Helmholtz 73 years old [from a pastel drawing by Leubach, 1894];
3. Helmholtz aged 70, lecturing, photographed by Mr Man (there is a crack across the slide);
4. Fallpendel für Zeiterinnerung;
5. Vibrationsmikroskop und Opthalmometer;
6. Doppelsirene Zur Erzeugung von Differenz in Summations Tönen und Teile des Vocalapparats.