midnight
He was arguing the case in his mind . What he had promised was , to consider the fifty marks as a debt of honour . Now a debt of honour must be paid within twenty-four hours . No doubt , thought the Count , it would not be altogether impossible to consider the twenty-four hours as extending from midnight to midnight . The Russians have an expression which means a day and a night together -- they call that space of time the sutki , and it is a more or less elastic term , as we say `` from day to day , '' `` from one evening to another . '' Rooms in Russian hotels are let by the sutki , railway tickets are valid for one or more sutki , and the Count might have chosen to consider that his sutki extended from the time when he had spoken to Fischelowitz until twelve o'clock on the following night . But he had no means of knowing exactly what the time had been when he had been in the shop , and his punctilious ideas of honour drove him to under-estimate the number of hours still at his disposal .