Bill: thank you for posting this fascinating snippet. I expect that something similar probably occurred in most English-speaking coal-mining areas. ray in oz ----- Original Message ----- From: "Bill Hazelton" <bhazelto@comcast.net> ... > Below is an explanation in mining in Scotland. I've seen it used in > meat-packing and may have been common in many occupations. The concept was > even used by doctors > in WWI to quantify a "cripples" ability to work and hence help determine > what type of occupation they may be capable of doing. > > Bill Hazelton > Memphis ...