This a placeholder for a small group of letters that have been seen. 

Christie's sold 2 letters from BR to Waley on 22 Nov. 2011 in a lot with about 120 other letters to Waley. The dates of Russell's 2 letters are not given. This quotation from one of them is: "The human race appears to have made little progress since that period, and the advice to wise men, contained in it, has unfortunately not been adopted." The buyer, who paid £15,000, was not disclosed.