Einstein announces four papers to his friend.
The first paper \u201Cdeals with radiation and the energetic properties of light\u201D \u2013 the paper on the light-quantum hypothesis.
\u201CThe second paper is a determination of true atomic size from diffusion and internal friction.\u201D This is Einstein\u2019s dissertation.
\u201CThe third proves that, under the requirements of molecular theory, the heat in bodies suspended in fluids [...] must execute a perceptible, random movement\u201D \u2013 his work on Brownian Motion.
\u201CThe fourth [...] is an electrodynamics of moved bodies applying a modification of the theory of space and time.\u201D In this work Einstein formulates his Special Theory of Relativity.