The contribution by Domenico Pacini to the Cosmic Ray Physics
  Between 1900 and 1913 several people were investigating about the unknown radiation, later identified as Cosmic Rays. Several experimentalist tried to identify the origin of this radiation and in particular Victor Franz Hess, Theodor Wulf and Domenico Pacini. Among them Domenico Pacini had a crucial role to address the answer to the origin of this radiation in the right way, and V.F.~Hess performed the complete set of measurements that definitively excluded an origin connected to the soil radioactive elements. However the most interesting and may be surprising point it that these pioneers defined 1 century ago the three experimental lines to study the Cosmic Rays: from space, on ground and underground and using only electroscopes. Domenico Pacini in particular may be considered the pioneer of the underground measurements on Cosmic Rays and Hess with his set of systematic measurements with balloon flights, originated the air-space studies on Cosmic Rays. 
Nicola Giglietto
physics.hist-ph hep-ex