October 1992

Potash

in Early Western New York

by

Robert G. Koch

An article in American Heritage of Invention & Technology celebrates the first U. S. Patent, issued July 31, 1790, and explains how "it saved what was then America's leading export industry." The patent document which bears the signatures of George Washington, Edmund Randolph, and Thomas Jefferson was issued to Samuel Hopkins then of Pittsford, Vermont, and later of Pittsford, New York. Hopkins, his wife and five of their children followed his cousin, Caleb, an early Pittsford settler, to Western New York around 1810. His wife Betsy died here in 1813. Hopkins remarried and lived here until his death in 1840. He is buried in Pittsford's Pioneer Burying Ground.

Patent No. 1 was for an improvement "in making of Pot Ash and Pearl ash by a new Apparatus and Process. As the article explains. "Potash is an impure form of potassium carbonate mixed with other potassium salts. Until the 1860s it was derived solely from the ashes of hardwood trees and certain other plants…Pearl ash is a [pearly colored] less impure form of potassium carbonate." Potash was used until the 20th century in "making soap and glass, dyeing fabrics, baking, and making saltpeter for gunpowder." It is still used in fertilizers.

In the 18th century England imported potash from the American colonies and Russia. The best yields came from "elm, ash, sugar maple, hickory, beech, and basswood" trees that grew well in New England and southern Canada and west to Minnesota. But in New England by the end of the 18th century "farmers and householders were down to cooking and heating ashes…Moreover to assure [their] firewood supply, one-fifth of the typical farm had to be kept wooded. People began to try to extract more salts from these ashes and even to obtain potash from previously discarded waste ash. The potash industry was in crisis. Enter Samuel Hopkins."

Hopkins's patented process called for furnace burning raw ashes and reburning the residues. As new hardwood lands were opened and as village asheries using the Hopkins methods under license began to replace processing by individual farmers, "the United States remained the world's leading producer of potash," until the 1860s, after which mined deposits in Europe made Germany the leader.

Meanwhile potash making was important to cash-starved settlers clearing American hardwood forests for agriculture. New York agricultural historian Ulysses Hedrick reports that a "settler clearing…10 acres could make a ton of potash which would sell for $200." Hedrick adds, "In regions where lumber and lumber products could not be marketed potash from ashes incidental to the clearing of every piece of forest land was long sovereign of all money-making products. A careful farmer could usually pay for the clearing of his land from the sale of potash." A major advantage was of course that it was relatively economical to transport.

Hedrick continues: "Out of the sale of black-ash and pearl-ash most farmers paid taxes, hired labor, bought clothing and tools, and might have a little over for a small purchase at the general store. From 1805 to 1825 New York sold an average per year of $300,000 worth of potash most of it from the Genesee country…" Some of that was shipped on Lake Ontario from the Genesee River to Montreal.

Neil Adams McNall in his History of Agriculture in the Genesee Valley reports that land agents sometimes provided kettles for ash preparation. Even fairly casual techniques were rewarding. In 1807 James Wadsworth wrote that, "The ashes which can be scraped off an acre after a good burn are worth from $4 to $8." He claimed that two men could make a ton of potash per month at an average value of $150 a ton, somewhat less than the figure cited by Hedrick.

The article on Samuel Hopkins U. S. Patent No. 1 concludes: "The forest-based potash industry is now long gone but it was essential in the early years of the nation and Samuel Hopkins's patent permitted it to thrive. Potassium salts continue to be invaluable industrial and agricultural chemicals and a stream of important patents concerning them has followed Samuel Hopkins's down to this day. Moreover, his exemplary disclosure, marketing plan, and license agreements set worthy precedents for all subsequent inventors."

© 1992, Robert G. Koch

Index to articles by Robert G. Koch

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