Their business traded wheat, iron, and seal furs and oil. The businessmen partnered with Jean-Baptiste Bouchette in 1765 to take advantage of his trading post and Gulf of Saint Lawrence fishery. They also bought a share of an ironworks in 1767, although they sold it a few years later.
In 1770 they entered into a long term lease for the King’s Wharf in Quebec, a vital resource for commerce in the city.
With four stills, four boilers and eight evaporation tubs, the distillery produced spirits, beer and an invention of Taylor"s called "essence of spruce for making beer", which was exported to New York and the West Indies. Their fortunes seemed to decline in the subsequent decades as they sold property and the distillery, sublet the King"s Wharf, borrowed money and sold their shares in the bridge.
The partnership ended with Johnston"s death in 1800. The firm"s assets were split between Purss and Margaret Macnider, Johnston"s widow.
Purss played a role in the city"s public life.
He was an important figure in the Quebec Fire Society. In 1787 Purss became a lieutenant in the militia and was promoted to captain around 1799. He served as assessor in 1797.
Purss died on 8 April 1803.
Having never married, his estate was left to relatives in Britain and to his partner"s widow.