In order to increase the rate of detection with a higher flux of cosmic rays, the equipment was moved to the Pic du Midi de Bigorre observatory in the Pyrenees. The existence of the particles was confirmed by a group from the California Institute of Technology led by Carl Anderson, and the Butler group continued to study them and found that there were two types, hyperons and mesons. Butler's and Rochester's discovery may be seen as the first step towards understanding of the quark structure of matter.