'Cosmic rays were first detected by V. F. Hess during a flight by one of these'
a hot air balloon
SCIENCE: Cosmic rays were first detected by V. F. Hess during a flight by one of these
Cosmic rays were first detected by V. F. Hess during a flight by one of these
Cosmic rays were first detected by V. F. Hess during a flight by one of these
SCIENCE
a hot air balloon
SCIENCE