"cosmic rays"

Do you know who first used the current name of the field "cosmic rays"?

The answer is Robert A. Milikan.

He first used this term to describe the cosmic radiation. He set up some experiments to measure the altitude dependence of the ionization of the air. His aim was to disprove the results of Hess and Kohlhorster who previously showed that the ionization of the air increases with altitude.

Victor F. Hess was the first person who discovered cosmic rays in 1912 doing his measurements in a balloon to altitudes of 5 km and received the Nobel prize in 1936 for his discovery.