Milieu einer Kindheit: Kindheit, Aetheraufsatz und Revolution
Letter from Paul Habicht to Albert Einstein
4 July 1908, facsimile
In 1906, Einstein is occupied with small oscillations in voltage in capacitors, which are similar to Brownian Motion. For the experimental test he requires a very sensitive measurement instrument. Its invention keeps him and the Habicht brothers busy over the next years.