An asbestos KCl bridge and a simple calomel electrode

Our plain-English summary of An asbestos KCl bridge and a simple calomel electrode, by C.E. Zobell, S.C. Rittenberg (Science, 1937).

The study

• Authors: C.E. Zobell, S.C. Rittenberg
• Journal: Science
• Published: 1937;86(2239):502
• Read it: PubMed · Publisher

In plain English

This 1937 one-page note in Science was not a health study. It described a piece of laboratory equipment that used asbestos as a material. The authors, at the Scripps Institution of Oceanography, needed to measure oxidation-reduction potential and pH at different depths inside narrow anaerobic tubes 360 mm long. To do this, they made a salt (potassium chloride) bridge by cleaning small asbestos threads in dilute acid and water, heating them in a gas flame, and sealing them into the end of a glass tube. The asbestos thread let the salt solution leak out slowly, and the size of the fiber controlled the rate of leakage. They reported working results with threads that leaked less than 0.01 cc per hour, and bridges as long as 400 mm and as thin as 0.2 mm. They also described a simple matching calomel electrode. The authors stated that the bridge proved entirely satisfactory, was easy to prepare, and was sturdy enough to withstand sterilization. The note did not name the type of asbestos and did not discuss health effects or exposure of the people making or using the device.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: short technical note describing a laboratory apparatus; not a study of people or animals
• Who was studied: no human or animal population; the device was built for measurements at different depths in narrow anaerobic oval tubes 360 mm long, at the Scripps Institution of Oceanography, University of California, La Jolla
• Exposure: asbestos threads (fiber type not named) used as a component of a potassium chloride bridge; the threads were cleaned in dilute hydrochloric acid and water, heated in a gas flame, and sealed into glass tubes; no human exposure was measured or discussed
• Main results:
  • The authors made asbestos bridges 400 mm long and only 0.2 mm in diameter, though most of their work used tubes 1.0 to 3.0 mm in diameter
  • The rate at which the salt solution leaked through the bridge was controlled by the size of the asbestos fiber used
  • Satisfactory results were obtained with tiny threads that let less than 0.01 cc of potassium chloride solution leak per hour
  • The authors stated that the whole apparatus could be built from a fifteen-cent Y-tube in fifteen minutes
• The authors' conclusion: The authors concluded that the asbestos bridge proved entirely satisfactory, was easy to prepare, and was sturdy enough to withstand sterilization

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