IN his tribute to Lord Rutherford in NATURE of October 6, Prof. A. S. Eve states that Lord Kelvin died in unbelief of Rutherford's atomic theory. Mr. C. Turnbull, 21 Percy Park, Tynemouth, North-umberland, has pointed out that this is incorrect. In his presidential address to the Physical Society (January 1936), Lord Rayleigh (p. 221) states that Kelvin argued emphatically with Rutherford and himself against the atomic origin of the energy. Rayleigh asked him to make a bet of five shillings that within three (or six) months he would admit that Rutherford was right. Within the allotted period Kelvin came round, and at the British Association he made a public pronouncement in favour of the internal origin of the energy of radium. He also produced the five shillings in settlement of the bet.