In the novel The Floating Admiral, Mr Tolwhistle is the stationer in Whynmouth. He does not appear in person, but Inspector Rudge speaks with him on the telephone.
Mr Tolwhistle supplies Admiral Penistone with a late edition of the London Evening Gazette, which his boy delivers to Rundel Croft every evening at about 9 p.m. He also supplies Reverend Mount with newspapers, but according to him, the vicar had recently cancelled his subscription to the late London Evening Gazette.
Mr Tolwhistle marks one of the copies of the Evening Gazette with the name "Admiral Pennystone". This is apparently not uncommon, as it is described as being "one of Mr Tolwhistle's characteristic mis-spellings".