The Question and Answer section for The Poems of William Blake is a great resource to ask questions, find answers, and discuss the novel.
There is a nostalgic fondness for memories made on the pastoral paradise. The old remember the treasured moments spent on the Echoing Green,
Such, such were the joys
When we all, girls and boys,
In our youth-time were seen
On the echoing green.'
The white hair signifies age and experience.
Tom Dacre, cried when his hair was shaved to prevent vermin and soot from infesting it.