Copy letter from Herbert Rix, to Joseph Gould, 16 Shakespeare Street, Nottingham 'Dear Sir, I understand that you are willing to show at our next Soiree your "Twin Elliptical Pendulum", and I am instructed by the Soiree Committee to ask whether you can refer me to any of our Fellows who has seen this apparatus and could speak for its novelty and interest. I am, yours truly, H Rix Asst. Sec. R.S. [Assistant Secretary, Royal Society]'. 6 April 1894