A New Hard Component of the Cosmic Ultra-Radiation

Abstract

PROF. KOLHÖRSTER has kindly directed my attention to a possible misunderstanding of the statement “a hitherto unknown component” in my communication entitled “A New Hard Component of the Cosmic Ultra-Radiation”¹. This statement, which referred to the harder Kiirunavaara component, was not intended in any way to dispute Kolhörster's earlier discovery of a very hard radiation capable of penetrating more than 500 m. of water. I had, however, overlooked that Kolhörster has also mentioned² a small decrease of the ionisation even down to 700 m. of water found by him so early as 1928 in the Stassfurt mines; it is evident that the whole radiation found by him should not be identified with the softer Kiirunavaara component alone.