"Surely the songster was westering home to Islay from the Scottish mainland?" - Boab
I believe Boab is right. This was my mother's party piece in Scotland and she sang it at her 80th Birthday party. A year later she passed away. I grew up understanding that it was an Islay native, who had moved to the big city, Glasgow, as many of the Islanders were forced to do in seek of work. He was comparing stories of China and the Orient, brought back from the sailors on the merchant ships, to his beloved island of Islay and yearned to be back there.