This man invented the current balance and a notable compass for the British Navy. He estimated the Earth to be at most forty 
This man invented the current balance and a notable compass for the British Navy. He estimated the Earth to be at most forty million years old and helped in the design and laying of transatlantic telegraph cables. This baron co-discovered the effect by which gases grow cooler as they expand; he co-names that effect with James Joule. He also names a scale in which zero degrees is equal to negative 273 degrees Celsius. For 10 points, name this Irish scientist who names a temperature scale that includes absolute zero.
This man invented the current balance and a notable compass for the British Navy.
Lord {Kelvin} [or {William Thomson}, {1st} Baron {Kelvin}; or {William Thomson}, {1st} Baron {Kelvin}]