A note in the autograph of Thomas Telford, engineer, at London, of 'Improvements necessary to be Undertaken' to the Holyhead Road, together with an estimate of the cost, 26 March, 1822 (references to portions of the road west of Bettws y Coed, between Cerig y druidion and Glyndyffws, between Glyn Dyffws and the Druid, between Corwen and Owen Glyndwrs Hill, and between Rhysgog and Llangollen); and a holograph letter from James Watt, engineer, London, to Robt. Muirheid, Glasgow, 1814 (advice in connection with a voyage along the Welsh coast, from Amlwch to the Bristol Channel).