Slow going today

I've been doing some reading today, then continuing to write the chapter of the Hugh Stowell Brown autobiography I started yesterday.
It's slow going because there's so many historical details to fill in and get right. Almost every sentence prompts a question:
- Was Birmingham a city or a town in 1840? (town)
- How did a land surveyor work? (he threw a chain across the land)
- Who were the strange dark-skinned people of Biddulph Moor? (Saracens, maybe, or gypsies)
...and many more. It's been facinating, but frustratingly slow. I think the chapter is half way there now.
Now I want to carry on with it and get it finished, but tomorrow I have to go to work. The weeks of this sabbatical are slipping by very quickly.