Question Author
Stuey: I've just looked at your posting on NAWCC, thank you. The weight doesn't drop in 12 hours. It takes 7-8 days but the clock just stops after 12 hours - or at least it did. It's been running since I started this post, I know we have a presence in this house - maybe he will allow it to run without stopping it :)
Either way, we'd like to know more about it and going on the information given already on the website, I'm pretty impressed! Dated around the 1700's :)