Apparently, Adams communicated his work to James Challis, director of the Cambridge Observatory, in mid-September 1845, but there is some controversy as to how. On 21 October 1845, Adams, returning from a Cornwall vacation, without appointment, twice called on Astronomer Royal George Biddell Airy in Greenwich. Failing to find him at home, Adams reputedly left a manuscript of his solution, again without the detailed calculations. Airy responded with a letter to Adams asking for some clarification. It appears that Adams did not regard the question as "trivial", as is often alleged, but he failed to complete a response. Various theories have been discussed as to Adams's failure to reply, such as his general nervousness, procrastination and disorganisation.