I might find this very useful. I recently came across some graphs showing the link between rainfall and water levels in Tresavean mine. As you know the Cornish mines were very wet for various reasons. In 1909 Basset Utd was pumping 3 million gallons a day!
Anyway the graphs were blueprints and also the writing was miniscule. Getting a decent image from a blueprint was a bit of a nightmare. Anyone else had a problem with blueprints or, as is more likely, is it my lack of expertise? 🙂
The past is a foreign country: they do things differently there.