Throughout the duration of his tour, Spencer sent many letters and postcards to his parents, who he kept up to date on his itinerary and thoughts. From within the Soviet Union, Spencer sent two postcards and two letters. A particularly interesting letter addressed to Spencer is also transcribed below.
| Correspondence | Sender | Recipient | Date Sent/Received |
|---|---|---|---|
| Postcards | H. Spencer Clark | John Clark and Esther Louisa Alexander | July 25 and 31, 1931 |
| Written Letter | H. Spencer Clark | John Clark and Esther Louisa Alexander | August 1, 1931 |
| Written Letter | H. Spencer Clark | John Clark and Esther Louisa Alexander | August, 1931 |
| Typed Letter | W. Purser | H. Spencer Clark | October 31, 1931 |
