[Based on a conversation at colgaffneyis dance group last night.]

I was asked whether a bubble level (spirit level) was in period (c. 1630)for colgaffneyis. I suspected not, but said that I would check my copy of Moxon. After we got home I did so. There is a drawing of a level in Moxon, but it is definitely of the plumb line type.

Also, according to this Wikipedia article (usual disclaimers about Wikipedia, but I actually think this article is OK), the spirit level was invented c. 1660. Moxon might have known about it, but if so was being conservative (or cheap). In any case, for colgaffneyis period, we need to use the plumb line type.

Before finding the Wikipedia article, I mentioned our talk to mia_mcdavid. She suggested the spirit level might have come from the late 17^th century, the time of the early Royal Society. She is absolutely correct. It is a product of that time and that particular international scientific culture.