A scientist/academic born after 1850, but dead now. Let's assume temporarily that that means he was born before 1920.
Assuming 20 years of age before notable work began, that means someone who was prominent no earlier than 1870.
And a lot of scientific advances from 1870 through 1940 came from German-speaking scientists - Einstien, Bohr, Heisenberg, etc.
So let's see if we can focus on this group or not...
Question:
Was the person's first language German (i.e. from Germany, Austria, Switzerland or another German-speaking country) ?