Unpublished paper and letter, 'Observations on the plan proposed by Mr Parrot of St Petersbourg [Petersburg] for mending the hole over the tunnel, securing the works against future irruption [upsurges] and in case of any irruption [upsurge], for saving the men' by Mc I [Marc Isambard] Brunel Brunel summarises the work of Georg Friedrich Parrot relative to a method for repairing a hole present in the earth above a tunnel, caused by an upsurge of a river. He also explains how further upsurges would be prevented and how workers would be saved should another accident occur. Preceded by a covering letter from Brunel to William Hyde Wollaston. An ink inscription on covering slip reads 'from Dr Wollaston's Papers'. Subject: Engineering 16 June 1828