Alum and Alkali Works

On Woods map this is apparently surrounded by ballast hills - though the works is not shown on the 1st edition OS map. The impetus to produce alkali came largely from the needs of the local glass trade. In 1762, Isaac Cookson, glassmaker, set up an alum works on land between the present ferry landing and Mill Dam. The alum was to be used as a source of potash salts in his glass houses. The clay containing aluminium salts (alum shale) were brought from Whitby. Around 1780 a small factory was set up on a hill-top near Mill Dam to make sulphuric acid by the chamber process. The site became known as Vitriol Hill. There was a public protest in 1823.