Correspondence with John Nye concerning the use of radio echo sounding to determine the thickness of ice sheets Correspondence on various aspects of radio echo sounding research, in particular discussions around using radio echo sounding to assist with deep core ice drilling in Greenland, and on survey flights in Antarctica. The field research in Antarcica was delayed, initially due to the necessary equipment not being ready in time and later by a researcher being unable to travel to the South Pole Research Station on medical grounds. Some correspondence relates to equipment testing being carried out at the Jungfraujoch research station in Switzerland. Some manuscript notes by Nye and a small collection of reprints are also present. Principal correspondents include Joseph Fletcher, Charles Swithinbank, Preben Gudmandsen, Albert Crary, Michael Walford, Robert Rutford, H Jay Zwally, B Lyle Hansen, Marcel de Quervain, and Maxwell Gage. 1972-1973