Joules and Keswick

James Joule did his research on energy nearly 200 years ago. I was reading about his experiment where he allowed a falling weight to turn a paddle wheel in a barrel of water. He measured the temperature of the water. It went up because the mechanical work gave extra kinetic energy to the molecules in the water. I was thinking about trying to recreate it in my lab. Suppose I allowed a 1kg mass to fall 1m. It would lose mgh = 1 x 10 x 1 = 10 Joules of gravitational potential energy. If all of this went to raise the temperature of the water I'd be using dQ = mcdT. Say I used a 1 litre tub of water. The mass of water would be 1kg. Specific heat capacity of water = 4200 J/kg/degree C. So change in temperature dT would be 10/4200. To get a convincingly large temperature rise I'd need a much, much larger mass to fall through a much bigger distance. I wonder what he used...