Question: Who is the paternal grandfather of Anders Knutsson Ångström?
Sentence (from "Knut Ångström"): He focused his research work on investigating the radiation of heat from the sun, terrestrial nocturnal emission and its absorption by the Earth's atmosphere, and to that end devised various delicate methods and instruments, including his electric compensation pyrheliometer, invented in 1893, apparatus for obtaining a photographic representation of the infra-red spectrum (1895) and pyrgeometer (
Relevant evidence: No