Box 1
Bentley, Richard, (1662-1742) correspondence
Box 1
Butler, Nicholas Murray correspondence
Box 1
Einstein, Albert correspondence
Box 1
Michelson, Albert Abraham correspondence
Box 1
Montague, Charles, 1st Earl of Halifax correspondence
Box 1
Oppenheimer, Robert correspondence
Box 1
Strutt, John William, 3rd Baron Rayleigh correspondence
Box 1
Weismann, August correspondence
Box 1
Butler, Nicholas Murray photograph
Box 1
American Physical Society correspondence, 1929-1941
Box 1
Columbia University correspondence
Box 1
Columbia University correspondence
Regarding leave of absence/disability/retirement.
Box 1
Teacher's College correspondence, 1940-1941
Regarding lease of apartment
Box 1
Correspondence with Frances Orr
Box 1
European trip correspondence, 1927
Mentions various eminent physicists.
Box 1
Letters to family from Europe, 1927
Box 1
Letters of condolence to Frances Orr Severinghaus, 1947, 2 folders
Box 1
General correspondence, 19 folders
Box 1
Willard Severinghaus's last will and testament, 1927 January 28