O. S. and N. S.: On consultation with several specialists I have learned that the abbreviations O. S. and N. S. relate to the difference between the old Julian calender used in England and the Gregorian calender which was the standard in Europe. In the mid 18th century it is said that this once amounted to a difference of eleven days. To keep track of the chronology of letters back and forth from England to France or other countries in mainland Europe, Chesterfield inserted in dates the designation O. S. (old style) and N. S. (new style). Chesterfield demonstrates his classical education by frequent words.
