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Goldbeater's skin is the processed outer membrane of the
intestine of an animal, typically cattle, which is valued for its strength against tearing. The term derives from its traditional use as durable layers interleaved between sheets of gold stock during the process of making
gold leaf by
goldbeating, as a batch process producing many "leaves" at the same time. In the early modern production of
airships, application of its high strength-to-weight ratio and reliability were crucial for building at least the largest examples.
Manufacture
To manufacture goldbeater's skin, the gut of
oxen (or other
cattle) is soaked in a dilute solution of
potassium hydroxide, washed, stretched, beaten flat and thin, and treated chemically to prevent
putrefaction. A pack of 1,000 pieces of goldbeater's skin requires the gut of about 400 oxen and is 1 inch (25 mm) thick.[citation needed]
Up to 120 sheets of gold laminated with goldbeater's skin can be beaten at the same time, since the skin is thin and elastic and does not tear under heavy
goldbeating. The resultant thickness of gold leaf can be as small as 1 μm-thick.[citation needed]
Applications
Goldbeater's skin is used as the sensitive element in
hygrometers, since its
hygroscopic behavior includes contraction or expansion in response to atmospheric humidity.
Joseph Thomas Clover invented an apparatus for measuring the inhalation of
chloroform in 1862; it included a large reservoir bag, lined with goldbeater's skin to make it airtight, into which a known volume of liquid chloroform was injected, while its contraction or expansion was monitored.[2]
Due to its transparency, strength, and fairly uniform thickness, goldbeater's skin is used to repair holes and tears in manuscripts written on
vellum.
Large quantities of goldbeater's skin were used to make the gas bags of early balloons created by the
Corps of Royal Engineers at
Chatham, Kent starting in 1881–82 and culminating in 1883 with The Heron, of 10,000 cu ft capacity. The method of preparing and making gas-tight joins in the skins was known only to a family called Weinling, from the
Alsatia London area, who were employed by the Royal Engineers for many years. The British had a monopoly on the technique until around 1912, when the Germans adopted the material for the internal gas bags of the "
zeppelin"
rigid airships, exhausting the available supply: about 200,000 sheets were used for a typical
World War I zeppelin, while the
USS Shenandoah (ZR-1) needed 750,000 sheets.[3] The sheets were joined together and folded into impermeable layers.[3]
Goldbeater's skin (sometimes also called "fish skin" in this context) is sometimes used to seal
oboereeds to prevent them from leaking air.
^Sykes, W.S. (1960), Essays on the First Hundred Years of Anaesthesia, Vol. 2, Churchill Livingstone, Edinburgh.
ISBN0-443-02866-4, p. 8.
^
abSteadman, Mark (2006-05-01).
"The Goldbeater, the Cow and the Airship". MuseumsPosten, Post & Tele Museum Online Magazine. Copenhagen, Denmark. Retrieved 25 December 2020.
^François Lebrun, "Les 'Funestes secrets'", Les Collections de l'Histoire, 2nd quarter 2006, p. 63.
ISSN0182-2411.