Among Walsingham's correspondents was George Chalmers, a merchant of Edinburgh. Chalmers was no mere maker of crude and impracticable suggestions. He had thirty years before been instrumental in shortening the course of post between Edinburgh and London. Before 1758 the Great North Mail, as it was called, went three days a week and occupied eighty-seven hours in going from London to Edinburgh, and 131 hours in going from Edinburgh to London. Thus, a mail leaving Edinburgh at twelve at night on Saturday did not reach London until eleven o'clock on Friday morning. Chalmers, in a paper of singular ability, dwelt upon the absurdity of the various detentions, ranging from three hours at Berwick to twenty-four hours at Newcastle, which made the course of post longer by nearly two days in one direction than in the other, and shewed how, by avoiding these unnecessary delays and getting rid of a diversion of twelve miles to York, the distance might be accomplished between London and Edinburgh in eighty-two hours, and between Edinburgh and London in eighty-five. The plan was adopted, and some years later, in recognition of its merits, Chalmers received from the Government a gratuity of £600. More recently he had prevailed upon the Post Office to increase from three to six days a week the service between London and Edinburgh, and from Edinburgh to the principal towns in Scotland; and in London, at his suggestion, the letter-carriers who collected letters by the sound of bell, or bellmen as they had begun to be called, were being employed after nine o'clock at night.