In these letters to Caroline Watts, a young friend and teacher in Durham, England, Spencer writes principally about the teaching of geometry and astronomy. He also comments on current political and literary events in England, including John Bright's defeat, the Corn Laws, and theories about health and religion. There is frequent mention of his brother Thomas Spencer, and his son Herbert Spencer.

The most stellar member of a stellar family, Elisha Kent Kane was among the most popular American explorers of the mid-nineteenth century, a hero in the tragic mode. Born in Philadelphia in 1820, the son of John Kintzing Kane and Jane Duval Leiper, Kane studied medicine at the University of Pennsylvania before earning a commission as a naval surgeon. While in the Navy, Kane embarked on the succession of voyages to exotic locales that became the basis for his extraordinary fame. In 1843, he attended Caleb Cushing's first diplomatic mission to China as ship's physician, and subsequently traveled to the Philippines and Western Africa. Distinguishing himself in the Mexican War, Kane's greatest fame came from two expeditions to the arctic, aiming to locate the lost explorer, Sir John Franklin and to explore for evidence of the open polar sea. Kane died in 1857 while attempting to organize a third arctic voyage. Part of the Kane Family Collection, the Papers of Elisha Kent Kane contain a mix of personal and family correspondence with correspondence relating to all of Kane's explorations. Intelligent, articulate and very much a romantic, Kane's letters are expressive and passionate. The collection provides fine documentation of youth, his relationship with the Spiritualist Margaret Fox, and of course his travels to China and off the coast of Africa in 1846. Kane's two expeditions to the arctic are particularly well documented, with correspondence, notes, logbooks, diaries, and sketches, as well as Kane's post-expedition notes, writings, and lectures recounting his experiences.