Came across these two old photographs of Cooke's level - maybe 1920s? The one with the men in it is interesting for the difference it shows between the bores. It was also used in Compressed air magazine for 1921 as part of an article on the North Wales quarries.
Photograph:
🔗Maenofferen-Slate-Mine-Archive-Album-Image-93427[linkphoto]Maenofferen-Slate-Mine-Archive-Album-Image-93427[/linkphoto][/link]
🔗Maenofferen-Slate-Mine-Archive-Album-Image-93428[linkphoto]Maenofferen-Slate-Mine-Archive-Album-Image-93428[/linkphoto][/link]
Grahami
The map is the territory - especially in chain scale.