Autograph Letter Signed, to Sir Marc Isambard Brunel, thanking him for “the two plans of the Thames Tunnel, the pamphlets, and your letter with the drawings of the Entrance”, and repeating verbatim the comments made about the drawings by the geologists, Professor Buckland and Professor Daubeny. 4 pp. 7 x 4 inches, traces of former mounting at centre fold. Oxford, 21 August 1844. Robert Shelton Mackenzie (1809-1880), editor, biographer (including a Life of Charles Dickens), miscellaneous writer. He contributed biographies to ‘The Georgian Era’ (1832–4), and was engaged on the staff of several London newspapers. ‘Professor Buckland’s opinion was this “I consider it quite impossible that the Tunnel can now fall in. The quantity of water which each tidal change brings over it is immense, but then it does not strike the work, so as to injure it, but comes on it & goes from it gradually. I think the Tunnel may last for a thousand years. In fact (he added) until the materials themselves decay.” The tunnel was opened to the public on 25 March 1843.