Interesting reading...
I added the following information on the "stone" and its equivalency to the pound for your info: The stone, quarter, hundredweight, and ton were larger units of mass used in Great Britain. Today only the stone continues in customary use for measuring personal body weight. The present stone is 14 pounds, but an earlier unit appears to have been 16 pounds.
Calculations: 1 stone = 14.012 pounds - at 18-1/2 stone, that meant ...