"La Mer"

As Chatwin finally sails away from Patagonia he is treated to a rendition of La Mer by a Chilean businessman. There are two possible candidates:

The unexpected hit by French singer Charles Trenet, which has since gone on to be recorded by hundreds of artists, including Bobby Darin.   Listen on Spotify:  Charles Trenet: La Mer     Bobby Darin: Beyond the Sea  

Or Debussy's orchestral work in three movements.    La Mer I    La Mer II   La Mer III

Whichever, we can only assume it would have been a very bad rendition; played on a piano 'missing many of its keys.'