Goldbeater's skin is the processed outer membrane of the

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans an ...

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 Gold leaf is gold that has been hammered into thin sheets (usually around 0.1 µm thick) by goldbeating and is often used for gilding. Gold leaf is available in a wide variety of karats and shades. The most commonly used gold is 22-kara ...

by goldbeating, as a batch process producing many "leaves" at the same time. In the early modern production of

airship An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In early ...

s, 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 An ox ( : oxen, ), also known as a bullock (in BrE, AusE, and IndE), is a male bovine trained and used as a draft animal. Oxen are commonly castrated adult male cattle; castration inhibits testosterone and aggression, which makes th ...

(or other

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Adult females are referred to as cows and adult ...

) is soaked in a dilute solution of

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exp ...

, washed, stretched, beaten flat and thin, and treated chemically to prevent

putrefaction Putrefaction is the fifth stage of death, following pallor mortis, algor mortis, rigor mortis, and livor mortis. This process references the breaking down of a body of an animal, such as a human, post-mortem. In broad terms, it can be view ...

. A pack of 1,000 pieces of goldbeater's skin requires the gut of about 400 oxen and is thick. 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.

Applications

* Goldbeater's skin is used as the sensitive element in

hygrometer A hair tension dial hygrometer with a nonlinear scale. A hygrometer is an instrument used to measure the amount of water vapor in air, in soil, or in confined spaces. Humidity measurement instruments usually rely on measurements of some other q ...

s, since its

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance' ...

behavior includes contraction or expansion in response to atmospheric humidity. * During the

invention of the telephone The invention of the telephone was the culmination of work done by more than one individual, and led to an array of lawsuits relating to the patent claims of several individuals and numerous companies. Early development The concept of th ...

Alexander Graham Bell Alexander Graham Bell (, born Alexander Bell; March 3, 1847 – August 2, 1922) was a Scottish-born inventor, scientist and engineer who is credited with patenting the first practical telephone. He also co-founded the American Telephone and T ...

used a drum of goldbeater's skin with an armature of magnetised iron attached to its middle as a sound receiver. * In 1754, Vatican priest Antonio Piaggio used goldbeater's skin in one of the earliest attempts to unscroll and read the

Herculaneum papyri The Herculaneum papyri are more than 1,800 papyri found in the Herculaneum Villa of the Papyri, in the 18th century, carbonized by the eruption of Mount Vesuvius in AD 79. The papyri, containing a number of Greek philosophical texts, come fr ...

ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic pe ...

texts buried and hardened into carbonized lumps by the 79 AD eruption of

Mount Vesuvius Mount Vesuvius ( ; it, Vesuvio ; nap, 'O Vesuvio , also or ; la, Vesuvius , also , or ) is a somma-stratovolcano located on the Gulf of Naples in Campania, Italy, about east of Naples and a short distance from the shore. It is one of ...

. * The

North German Confederation The North German Confederation (german: Norddeutscher Bund) was initially a German military alliance established in August 1866 under the leadership of the Kingdom of Prussia, which was transformed in the subsequent year into a confederated st ...

printed 10- and 30-

groschen Groschen (; from la, grossus "thick", via Old Czech ') a (sometimes colloquial) name for various coins, especially a silver coin used in various states of the Holy Roman Empire and other parts of Europe. The word is borrowed from the late L ...

postage stamp A postage stamp is a small piece of paper issued by a post office, postal administration, or other authorized vendors to customers who pay postage (the cost involved in moving, insuring, or registering mail), who then affix the stamp to the f ...

s on goldbeater's skin to prevent reuse of these high-value stamps. * Joseph Thomas Clover invented an apparatus for measuring the inhalation of

chloroform Chloroform, or trichloromethane, is an organic compound with formula C H Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to PTFE. It is also a precursor to various ...

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. * Due to its transparency, strength, and fairly uniform thickness, goldbeater's skin is also used to repair holes and tears in manuscripts written on

vellum Vellum is prepared animal skin or membrane, typically used as writing material. Parchment is another term for this material, from which vellum is sometimes distinguished, when it is made from calfskin, as opposed to that made from other anim ...

. * Large quantities of goldbeater's skin were used to make the gas bags of early balloons created by the Royal Engineers at

Chatham, Kent Chatham ( ) is a town located within the Medway unitary authority in the ceremonial county of Kent, England. The town forms a conurbation with neighbouring towns Gillingham, Rochester, Strood and Rainham. The town developed around Chatham ...

starting in 1881–82 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 from Alsatia called Weinling who were employed by the RE 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 A Zeppelin is a type of rigid airship named after the German inventor Count Ferdinand von Zeppelin () who pioneered rigid airship development at the beginning of the 20th century. Zeppelin's notions were first formulated in 1874Eckener 1938, pp ...

rigid airship A rigid airship is a type of airship (or dirigible) in which the envelope is supported by an internal framework rather than by being kept in shape by the pressure of the lifting gas within the envelope, as in blimps (also called pressure air ...

s, exhausting the available supply: about 200,000 sheets were used for a typical

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was List of wars and anthropogenic disasters by death toll, one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, ...

zeppelin, while the USS ''Shenandoah'' (ZR-1) needed 750,000 sheets. The sheets were joined together and folded into impermeable layers. * Goldbeater's skin (sometimes also called "fish skin" in this context) is sometimes also used to seal

oboe The oboe ( ) is a type of double reed woodwind instrument. Oboes are usually made of wood, but may also be made of synthetic materials, such as plastic, resin, or hybrid composites. The most common oboe plays in the treble or soprano range. ...

reeds to prevent them from leaking air. * The

goldbeater's skin test Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' (from Anglo-Norman ''tanner'', f ...

is used to assess the

tannin Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' (from Anglo-Norman ''tanner'' ...

g properties of a compound. * In the eighteenth and nineteenth centuries, goldbeater's skin was also used as a material for condoms.François Lebrun, "Les 'Funestes secrets, ''Les Collections de l'Histoire'', 2nd quarter 2006, p. 63. .

Manufacture

Applications

See also

References

Further reading