The Royal Gunpowder factories at the end of the 18th to the beginning of the 19th centuries – part II . A LINK.

http://myneighborwellington.blogspot.com.au/2012/05/royal-gunpowder-factories-at-end-of.html

The information here on Sara's blog starts before the 18th century and goes through to the 19th century.
Keith.