Copy letter from Herbert Rix, to Professor William Edward Ayrton In answer to Ayrton's note of this morning Rix sends a copy of the proof so far as it is set up. Rix sends the proof on the strength of Ayrton's information that Lord Rayleigh [John William Strutt] has written to Ayrton on the subject. Rix asks however that Ayrton keep the proof private and not display it at the meeting. 21 January 1891