TY - JOUR T1 - The Ionisation Produced by an $ \alpha $-Particle. Part I JF - Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character (1905-1934) VL - 82 IS - 557 SP - 486 EP - 495 PY - 1909/07/31/ UR - http://dx.doi.org/10.1098/rspa.1909.0053 M3 - doi:10.1098/rspa.1909.0053 AU - Geiger, H. ER -