Editing Potash (section)

=== 18th century ===

==== Kelp ash ====
On the [[Orkney]] islands, [[kelp]] ash provided potash and [[soda ash]], production starting "possibly as early as 1719" and lasting for a century. The products were "eagerly sought after by the glass and soap industries of the time."<ref name="stkelp">{{cite news |title=Kelp Burning in Orkney |website=orkneyjar.com |publisher=Sigurd Towrie |url=http://orkneyjar.com/tradition/kelpburning.htm |access-date=2021-09-20 |archive-date=2023-05-14 |archive-url=https://web.archive.org/web/20230514013844/http://www.orkneyjar.com/tradition/kelpburning.htm |url-status=dead }}</ref>

==== North America ====
By the 18th century, higher quality American potash was increasingly exported to Britain. In the late 18th and early 19th centuries, potash production provided settlers in North America badly needed cash and credit as they cleared wooded land for crops. To make full use of their land, settlers needed to dispose of excess wood. The easiest way to accomplish this was to burn any wood not needed for fuel or construction. Ashes from [[hardwood]] trees could then be used to make [[Potassium hydroxide|lye]], which could either be used to make soap or boiled down to produce valuable potash. Hardwood could generate ashes at the rate of 60 to 100 [[bushel]]s per acre (500 to 900 m<sup>3</sup>/km<sup>2</sup>). In 1790, the sale of ashes could generate $3.25 to $6.25 per acre ($800 to $1,500/km<sup>2</sup>) in rural [[New York State]] – nearly the same rate as hiring a laborer to clear the same area. Potash making became a major industry in British North America. Great Britain was always the most important market. The American potash industry followed the woodsman's ax across the country.

====The first US patent====
The first [[United States patent law|US patent]] of any kind was issued in 1790 to [[Samuel Hopkins (inventor)|Samuel Hopkins]] for an improvement "in the making of Pot ash and Pearl ash by a new Apparatus and Process".<ref>[[wikisource:United States patent X1|Patent X1: the making of Pot ash and Pearl ash by a new Apparatus and Process (1790)]]. en.wikisource.org</ref> ''Pearl ash'' was a purer quality made by [[calcination]] of potash in a [[reverberatory furnace]] or kiln. [[Potash pit]]s were once used in [[England]] to produce potash that was used in making soap for the preparation of wool for yarn production.