In 1807, eight more were added. By 1809, production capacity had been increased further, with 26 vessels in total. This was further increased by six in 1811, taking the total number to 32 and were much larger, measuring 60 x 14 x 12 feet high, arranged in sets of two or three. The chambers were constructed to use external furnaces that burned the sulfur and supplied gas by use of a flue. These were supplied by Bealy and Radcliffe of Manchester.

In 1825, when the salt tax was removed, the factory