Prof. R. A. Millikan, discoverer of the Cosmic rays, has recently reported to the National Academy of Science a practical use for those rays. These are the most penetrating radiations known, far exceeding X rays and even the very penetrating gamma rays of radium in that respect.
©1930 by Iowa State Teachers College
"Cosmic Rays as Barometers,"
Science Bulletin: Vol. 3:
4, Article 9.
Available at: https://scholarworks.uni.edu/science_bulletin/vol3/iss4/9