“GOLD BEATER’S SKIN”

Sun (Auckland), Volume IV, Issue 986, 31 May 1930, Page 32

“GOLD BEATER’S SKIN”

MAKING DIRIGIBLES’ OVERCOATS Thousands of cattle have contributed from time to time to the making of dirigible airships. The membrane known for centuries as goldbeater’s sklu comes from an obsolete stomach or kind of appendix in certain animals, says an overseas exchange. For the past 20 years, Governments of Europe and departments in the United States have been seeking for a substitute for this precious membrane used in making gas-cells for lighter-than-air flying machines. The skins as taken from the cattle are small, and cost between lOd and Is 3d apiece. Ultimate proccesses bring the cost, measured in feet and inches, to about £2 a square yard. The size of a modern airship requires 30.000 square yards of membrane for its gas cells. Recognition of the value of the dirigible airships in war and commerce has spurred the world powers to seek for a less expensive material with which to line the great gas envelopes on which dirigibles depend for buoyancy. Goldbeater’s skin weighs less than three-quarters of an ounce to the square yard, and allows a minimum escape of gas. In finished form, applied to cotton cloth and covered with varnish, it weighs about 4oz to the square yard, which is considerably less than the best rubberised substitute yet produced.

Goldbeater’s skin for twenty centuries or more has been used as interleaving in hammering gold into leaf form. Placed between sheets of the skin it is possible to reduce the metal to 1-200,000 of an inch in thickness. Without interleaving the gold would cliug to the hammer when it was an eighth of an inch thick, and thereafter become impracticable for working without some artificial aid such as the skin described.