Hello ,
Update on the Letman Chemists of Chemistry ,Saltney.
The family lived at Chemistry house /workshop from about 1793 .Moving there from the Warwick area
The House had been established in 1781 by a Mr Thorp to extract Glauber's Salts and Sal ammoniax and to produce Black Ivory .He used the black Ivory in his production of buttons
John Letman was employed by a Mr Rigby around 1793 after he had purchased the business from Mr Thorpe and then expanded the production of black Ivory.
John's son ,Edward Letman, continued in his fathers footsteps, working and Living at Chemistry in Saltney .
He produced Black Ivory ,known now to a carcinogenic agent .The process to make the black Ivory used refuse animal horn and bone ,sounds unpleasant !.
I don't know when the business closed (maybe in the 1840's )
The house at Chemistry was still lived in during the 1890's .
I think that the area is now known as Chemistry Lane
Any further information very welcome