TY - JOUR T1 - On Small Longitudinal Material Waves Accompanying Light Waves JF - Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character (1905-1934) VL - 85 IS - 580 SP - 474 EP - 476 PY - 1911/08/15/ UR - http://dx.doi.org/10.1098/rspa.1911.0060 M3 - doi:10.1098/rspa.1911.0060 AU - Poynting, J. ER -