One of the four songs George wrote in India for the double white album in 1968.
The ending is a fortuitous accident during the recording session, as George Martin's assistant Chris Thomas later recalled.
It is a bottle of Blue Nun wine rattling away on top of a Leslie speaker cabinet.
Leslie cabinet is a kind of dresser invented in 1937 (by Donald Leslie) with rotating plates and microphones inside to create a tremolo effect at the end of an organ.