He discovered a manuscript of accounts from King James IV of Scotland that showed he paid two shillings for a bag of 'fut ballis' on 11 April, 1497. More evidence came with we came across several diary accounts of football being played in places like Stirling Castle, Edzell Castle and Carlisle Castle. The games were played on pitches smaller than the current regular football field, and featured between 10 and 20 men on each side.
These caissons always weigh the same whether or not they are carrying their combined capacity of 600 tonnes (590 LT; 660 ST) of floating canal barges as, according to Archimedes' principle, floating objects displace their own weight in water, so when the boat enters, the amount of water leaving the caisson weighs exactly the same as the boat. This keeps the wheel balanced and so, despite its enormous mass, it rotates through 180° in five and a half minutes while using very little power. It takes just 22.5 kilowatts (30.2 hp) to power the electric motors, which consume just 1.5 kilowatt-hours (5.4 MJ) of energy in four minutes, roughly the same as boiling eight kettles of water.