Kingsley, Charles Merchant. Charles Kingsley was one of several men who were associated with the Fred Gray Association, "a loose confederation of young men who seemed anxious to explore new possibilities of male-male affection" (Folsom & Price “Walt Whitman”). E. Miller explains that “during this period Walt [Whitman] was intimate with a group he called the Fred Gray Association. Not much is known about this circle. Gray, the son of a noted New York physician, took a medical degree after the war. Nathaniel Bloom became a successful merchant. Hugo Fritsch was the son of the Austrian consul. The others are only names: Charles Chauncey, Charles Kingsley, Ben Knower, Charles Russell, Perkins, and Raymond. From Whitman’s and their letters we can deduce that they were young men, that they drank and caroused together at Pfaff’s and elsewhere” (“Introduction” 11).  Walt Whitman described Kingsley as "a young man, upper class, at Pfaff’s &c--fond of training for boat-racing &c." (LC #8). 

References & Biographical Resources

Blalock, Stephanie M. "'My Dear Comrade Frederickus': Walt Whitman and Fred Gray." Walt Whitman Quarterly Review. 27.1 (2009): 49-65. 
In a letter to Whitman from March 21, 1863, Kingsley discussed the military travels of Fred Gray. 
 [pages:54-55]
Glicksberg, Charles I. "Walt Whitman in 1862." American Literature. 1934. 264-282. 
Described as a member of the upper class "fond of training for boat racing &c" who spent time with Whitman at Pfaff's in June and July of 1862.
 [pages:275]
Haynes, John Edward. Pseudonyms of Authors: Including Anonyms and Initialisms. New York, 1882. 
This text identifies the following pseudonym: C.K. (24).
 [pages:24]
"Literary Notes." New York Saturday Press. 18 Jun. 1859: 3. 
Miller, Edwin Haviland. "Introduction." The Correspondence of Walt Whitman: Volume I, 1842-1867. Ed. Edwin Haviland Miller. New York: New York University Press, 1961. 1-18. 
[pages:11]
Robinson. "On Some English Novels." New York Saturday Press. 14 Oct. 1865: 162-163. 
Whitman, Walt. "Letter to Hugo Fritsch, October 8, 1863." Walt Whitman: The Correspondence. Ed. Edwin Haviland Miller. New York: New York University Press, 1961. 158-160. 
Whitman asks Fritsch to excuse him to Charles Kingsley for not writing. 
 [pages:158]
Whitman, Walt. "Letter to Nathaniel Bloom, September 5, 1863." Walt Whitman: The Correspondence. Ed. Edwin Haviland Miller. New York: New York University Press, 1961. 141-143. 
Whitman mentions that he misses his dear friend Kingsley, and asks Bloom to send him his love
 [pages:143]
Whitman, Walt. Letter to Nathaniel Bloom. 1863. 141-143.