Johann Christian Senckenberg

18th-century Frankfurt physician and naturalist (later the founder of what became the Senckenberg Nature Museum and library) whose 1732 diary, Observationes in me ipso factae, is the earliest surviving record of Johann Konrad Dippel's own recollection of the 1706 Prussian blue accident — a secondhand transcription, 26 years after the event, of a participant's memory.

Matters to this vault narrowly but specifically: per Klaus Roth's own accounting of the evidence base for reconstructing the 1706 discovery, Senckenberg's diary is the closest thing to personal testimony that survives, which is itself the answer to the vault's open question about whether any primary account of the accident exists.

References

• claim-no-contemporaneous-1706-account-survives-for-prussian-blue-discovery
• Captures: 2026-08-27 (first vault mention)