Borax
2 of the 6 encyclopedias on this shelf carry an entry for Borax. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
Important: Safety Warning
This page directs the use of hazardous substances — such as benzine, gasoline, lye, or strong acids — for household tasks. These materials are highly flammable, corrosive, or poisonous, and the practices described have caused fires, burns, and poisonings.
In addition, this page recommends preserving food with chemicals such as salicylic acid, borax, or formaldehyde. These substances are toxic when eaten, and their use in food is now prohibited.
This information has been left in for historical purposes but should not be acted upon.
a white, salty crystal with a sweetish, alkaline taste. It is a compound of boron, sodium, and oxygen (Na2B4O7). It forms like ice around the shores of certain waters. American borax is obtained from the waters and deposits of saline lakes in California and Nevada. Large shipments are made from the volcanic lakes of Bolivia. Borax occurs in the hot springs of Tuscany and in certain brackish lakes of Tartary, Tibet, Ceylon, and China. Borax is used in blowpipe analysis. A little borax powder sprinkled in a joint facilitates welding and soldering. Theoretically a large dose of borax is poisonous, but no harm seems to come from its frequent use as a preservative. During the Spanish-American War, it may be remembered, an accusation was brought that meats furnished the troops were canned in borax. Borax ranks with alcohol and salt as a preventive of bacterial growth. It is a disinfectant. Borax water is used in washing the furniture, clothing, and bedding of the sickroom. Fresh borax water is used to rinse milk bottles, to freshen the teeth, and to spray a sore throat. Surgeons use boracic acid to sprinkle wounds. It is a milder antiseptic than listerine. Borax softens hard water and makes washing easier. About 40,000,000 pounds of borax are produced in the United States annually. The early use of long mule teams to haul borax from the Death Valley gave rise to the well known trade mark, 20-Mule-Team Borax. See Alkali ; Salt ; Death Valley
Collier's New Encyclopedia (1921)
a rather brittle, sweetish, alkaline mineral, found native as a saline incrustation on the shores of certain lakes in California, Persia, Tibet, India, China, Ceylon, and in parts of South America. When collected on the banks of the lakes it is impure, and goes by the name of tincal.
What Has Changed in the Last Century
Aiton's 1910 claim that "no harm seems to come from its frequent use as a preservative" is the one line that has decisively fallen: borax is no longer permitted in food, and in the European Union borate compounds have been classified as toxic to reproduction and restricted in consumer products. The geography of supply has shifted too. Both accounts point to lake incrustations in California, Tibet, Persia and South America, but the modern trade rests on huge buried deposits — the Kramer/Boron orebody in the Mojave, mined since the late 1920s, and above all Turkey, which now holds most of the world's known boron reserves and leads production. Death Valley's mule teams stopped hauling ore long ago, though the "20-Mule-Team" name outlived the mines as a brand and later sponsored the radio and television series Death Valley Days.
Written for this edition, 2026.