Copy letter from Herbert Rix, to J Milsted Spencer, Standard Weights & Measures Department, 7 Old Palace Yard, S.W. 'Dear Mr Spencer, I forgot to ask you for the key of the box containing the standard weight and measure. As you returned it locked, I presume the key is in your hands. Would you kindly return it at your convenience? Yours truly, Herbert Rix Asst. Sec. R.S. [Assistant Secretary, Royal Society]'. 20 July 1894