The Cardiff Giant confession
On 10 December 1869 Hull told the press that the Cardiff Giant was a fake. Yale's Othniel C. Marsh had already denounced it, but visitors still turned up.
Archaeology magazine and Wikipedia both date the confession to 10 December 1869: on that day Hull confessed everything to the press. By then the Cardiff Giant had met several setbacks, including a courtroom loss. On 25 November, Othniel C. Marsh, a Yale paleontologist, had written that it was recent work and, in his words, "humbug".
Central New York History says Marsh visited the figure in Syracuse and called it a clumsy fake, pointing to chisel marks that were still plain to see. It says Hull had already cashed out, and confessed on sensing that the hoax was over. It adds that the crowds still turned up and began calling the giant Old Hoaxey.
Wikipedia reports that on 2 February 1870 both giants were shown in court to be fakes, and the judge ruled that Barnum faced no liability for calling a fake giant a fake. It gives Hull's own account of his motive: he meant the hoax to be exposed, to show how easily believers were taken in, and to counter the belief that giants once walked the earth.
"On December 10, 1869, Hull confessed everything to the press,[17] and on February 2, 1870, both giants were revealed as fakes in court; the judge also ruled that Barnum could not be sued for terming a fake giant a fake.[18] Hull proclaimed that he did not confess because of the pressing criticism, but confessed proudly that he intended for the hoax to be exposed to reveal the tendency of the Christian community to believe in things too easily and to counter the fundamentalist belief that giants once roamed the earth.[6]"
- Giants (Archaeology, Nov/Dec 2005), Archaeology magazine, Archaeological Institute of America (2005)
- Cardiff Giant, Central New York History (cnyhistory.org, 2014)