William the son of Edward Bull
Like the other Cornish engineers, Richard Trevithick took an active part from the first in opposing the Birmingham patent, and he is said to have constructed several engines, with the assistance of William Bull (formerly an erector of Watt's machines), with the object of evading it. These engines are said to have been highly creditable to their makers, working to the entire satisfaction of the mine-owners. The issue of the Watt trial, however, which declared all such engines to be piracies, brought to an end for a time a business which would otherwise have proved a very profitable one, and Trevithick's partnership with Bull then came to an end.
On the 1st September, 1814, Uville, Henry Vivian, Thomas Trevarthen, and William Bull (of Chacewater, in Gwennap) sailed from Portsmouth for Lima in the 'Wildman,' taking with them four pumping engines
William Bull, Thomas Trevarthen's fellow traveller, was a witness to his will made on 24th July 1814.
July 1816 saw the dawn of the industrial revolution in Latin America, when one of the engines was started at the Santa Rosa Mine under the direction of William Bull
1817 Trevithick’s arrival was timely. Two engines were at work drawing water, and two were drawing ore, but in an imperfect state, Uvillé knowing nothing about erecting steam engines and Bull very little
1818 William Bull died in South America