Two University of Washington professors are granted the patent for seatron, an edible kelp product, on July 26, 1910.

  • By David B. Williams
  • Posted 7/14/2020
  • Essay 21061
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On July 26, 1910, University of Washington professors Theodore C. Frye and Carl E. Magnusson are granted the patent for seatron, a substitute for candied citron. Their plan involves collecting macroalgae, or kelp, which grows abundantly throughout Puget Sound, processing it to remove the kelps' bad taste, and adding sugar and flavors to create an edible product. They are not the only people interested in the local kelp. Another UW scientist, George Rigg, is also studying kelp for its possible use as a source of potash, which was used in the production of explosives and other less volatile products. Despite the earnest efforts of the three men, neither plan meets with success.  

The Kelp Highway

Kelp has been essential to people in the Pacific Northwest for thousands of years. Recent studies show that the first people to travel out of Asia to North America about 15,000 years ago may have followed what has been labeled the Kelp Highway. This ribbon of an ecosystem adjacent to the seashore, with its abundant variety of kelp species -- some tall and robust like bull kelp and giant kelp and others smaller, understory plants -- would have provided early travelers with an ideal area to travel. Thick with edible kelp and the numerous animals that inhabited what researchers call a kelp forest, the highway was relatively calm, away from the cold of the continental interior, and easy to navigate.

Long after people had settled this region, they continued to use kelp. The long stems, or stipes, aided fishers, who crafted long ropes from the stipes for deep sea halibut fishing. Growing at the end of the stipes were turnip-shaped bulbs, which could be dried and made into a container for holding water or fish oil. And the leaves, or blades, were used in diverse ways for cooking, as well as in canoes to make paddles quieter.

For non-Native residents, one of the most important early "uses" of kelp was as an indicator of shallow water. Because kelp favors shallow water, navigators long ago learned to avoid taking their boats through kelp forests. In Puget Sound, this led to cartographers incorporating snake-like squiggles on maps to designate kelp and areas to avoid. The use of kelp as a navigation aid also shows up in the Directory for the Pacific Coast of the United States, a detailed guide produced by the U.S. Coast and Geodetic Survey. It contains descriptions, horizon drawings, distance charts, latitude and longitude measurements, soundings, and bearings, basically any information a mariner would need to navigate safely in the waters between Washington and California. There are also copious details about kelp, such as where it grew and where it didn't and how to tell current strength with kelp. In the 1869 edition the author wrote, "In coming to Steilacoom, or bound direct for Olympia, a patch of kelp, with foul bottom, and less than three fathoms of water upon it, must be avoided" (Directory).

"Unsavory and Nauseating"

Then in the early 1900s, two University of Washington professors came up with a new idea for an edible use of kelp. Theodore C. Frye (1869-1962) was a professor of botany and Carl E. Magnusson (1872-1941) was an associate professor of electrical engineering when they began to experiment with Puget Sound kelp. Specifically, they were working with bull kelp (Nereocystis luetkeana), a fast growing annual that is a dominant plant in the region's kelp forests.

On May 26, 1906, Frye and Magnusson applied for a patent for "Process of Preparing Seaweeds for Food." They wrote that kelp bulbs and stalks were normally unfit for use as food but that acetic acid (C2H4O2) would destroy the plants' "unsavory and nauseating taste" (Patent). They added that further washing and boiling in a sugar and flavoring solution created a "valuable food product" (Patent).

That same year they built a small plant at Ballard to supply the local food market, with plans to open a larger plant in Anacortes, near their main source of kelp. Their goal was to sell what they called "seatron," as a substitute for citron, a candied substance perhaps best known in modern times for its use in fruitcake. Frye told a Seattle Times reporter, "Our production is much more digestible than citron, it is more pleasing to the taste, not so tough and will be sold cheaper" ("New Food"). In addition to making citron, they hoped to offer jams, angelica, and marmalades.

At the time, citron sold in New York for 19 cents a pound. Frye and Magnusson planned to sell seatron for a dime a pound with production running about 6 1/2 cents per pound. The Anacortes plant would operate about six months a year, during the maximum growth period of bull kelp. Profit on each ton would be about $70.

Seatron Sours, Potash Plummets

Four more years though would pass before the professors got a patent for their product. What they did in the meantime in regard to seatron is not clear, but finally on June 8, 1911, an unnamed Seattle Times reporter wrote of a seatron industry springing up on Puget Sound that might "revolutionize the citron market of the world" ("Manufactured Kelp"). Sadly for Frye and Magnusson their unique product fostered no such transformation; the world apparently didn't need a new fruitcake ingredient. But they were not alone in seeing a way to exploit kelp.

In December 1911, the U.S. Secretary of Agriculture submitted a report to Congress on fertilizer resources of the United States, in particular potash, a term now generally given to potassium chloride. Historically produced by leaching wood ash, then boiling the ashes in a large iron pot to concentrate the solids, hence the name, potash's primary use was in fertilizers, but it was also central in the production of black gunpowder, acetone, soap, glass, and alum. What concerned the U.S. government was the country's sole dependence upon Germany for potash. If the Germans, who obtained their potash from salt deposits, ever decided to stop shipping potash, not only would American farmers suffer, but so would the British, who required acetone to make cordite, or smokeless gunpowder. 

Desperate to find an American potash source, scientists scoured the country investigating potash salts in southwest desert basins, salt well brines, and potassium-rich minerals, but none showed much promise. The only high-quality, cost-effective source, according to researchers, was kelp, which they valued at more than $240 million, just on the Pacific Coast.

One of the scientists working for Agriculture was George Burton Rigg (1872-1961), a professor of botany at the University of Washington. In 1911 and 1912, he spent his summers surveying for bull and giant kelp in Puget Sound and the Strait of Juan de Fuca. Rigg produced more than a dozen maps showing the kelp forests, ranked from very thin to very heavy. The richest areas occurred in the San Juan Islands with numerous Medium Heavy and Very Heavy forests, though the single densest stand wrapped Smith Island, about halfway between Lopez Island and Port Townsend. Within the Sound proper, the southernmost kelp grew around Squaxin and Anderson Islands, both labeled as Heavy.

Before Rigg had completed his surveys and soon after he had started to announce some of his findings, such as Puget Sound's annual kelp harvest could be worth as much as $175,000, stories began to appear in locals newspapers announcing plans to build potash plants to exploit the local kelp. "There is every prospect that the enterprise in which they are to engage will constitute a big local industry," wrote a Seattle Times reporter ("Companies Will Develop").

Eventually two plants opened on the Sound, one at Port Townsend and one at Port Stanley on Lopez Island. But far more successful potash plants were built in Southern California, and neither of the local concerns amounted to much except a handful of jobs. Rumor has it that a German spy may have infiltrated the Port Stanley plant and killed one of the key employees, but no one has been able to verify the story. When World War I ended and Germany began exporting potash again, the Puget Sound plants closed.

Ecologists now see Puget Sound's kelp forests as a critical part of the ecosystem. They provide a nursery for rockfish and salmon and good habitat for animals as diverse as kelp crabs, herring, abalones, and sand lance. The forests have been found to be an important source of carbon for dozens of species. Like many species in the Sound, kelps have suffered from human-made changes to the ecosystem, but there has also been a push to recognize their importance and a subsequential commitment to protect these diverse and important ecosystems.


George Davidson, Directory for the Pacific Coast of the United States, (Washington D.C.: Government Printing Office, 1869), pp. 242; Theodore Christian Frye and Carl Edward Magnusson, "Process of Preparing Seaweeds for Food," U.S. Patent 965,382, July 26, 1910; "New Food to be Sold in Seattle," Seattle Post-Intelligencer, November 18, 1906, Sporting Section, pp. 4; "Manufactured Kelp May Replace Citron," Seattle Times, June 8, 1911, pp. 13; "Companies will Develop Sound Potash Industry," Seattle Times, October 2, 1913, pp. 9; David B. Williams, Homewaters: A Human and Natural History, (Seattle: University of Washington Press, 2021).

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