When is a Stone not a Stone, and Why?

[Steve]

One additional point to confuse things even more. How much a stone weighs depends on what you are weighing. 

A 'Stone' of wool can either be 14, 15, or 24 pounds.

A "Stone' of Beef or mutton is 8 pounds; not idea on pork. 

Dry goods and spices (flour, sugar, etc...) typically 8 pounds per 'Stone' also. 

A "Stone' of wax is 12 pounds. 

Which makes me wonder, how did a "Stone" of people become 14 pounds? 

Again, just curious.

Steve/bboyminn