In 1837 H.V. Crauford was granted an English patent for dipping in a bath of molten zinc protected from volatilisation by a layer of sal ammoniac, (ammonium chloride, NH4Cl). This appears to be derived from the work, in the previous year, of the French chemist Sorel. In the 1840s the process was used to produce agricultural and industrial goods and corrugated iron sheet for building purposes. (Dickinson, 1943-4). There had been earlier attempts in France, starting around 1740, to use zinc to replace tin to protect iron goods. The last of these early attempts to use zinc plating seems to have been to produce iron hammered saucepans in Rouen, France, which was abandoned shortly before 1786.