'The Penance', a story of Saki, is about a dead cat. I am trying to understand a phrase in the following sentence from that story:
That same evening when twilight was deepening into darkness Octavian took up his position as penitent under the lone oak-tree, having first carefully undressed the part. Clad in a zephyr shirt, which on this occasion thoroughly merited its name, he held in one hand a lighted candle and in the other a watch, into which the soul of a dead plumber seemed to have passed.
What is the meaning of the phrase 'dead plumber' in this context?