DUCTILITY

( Streckbarkeit , Germ.) is the property of being drawn out in length without breaking, po e ed in a pre-eminent degree by gold and silver, as also by many other metals, by gla in the liquid state, and by many semifluid resinous and gummy substances. The spider and the silk-worm exhibit the finest natural exercise of ductility upon the peculiar viscid secretions from which they spin their threads. When a body can be readily extended in all directions under the hammer, it is said to be malleable, and when into fillets under the rolling pre , it is said to be laminable. Table of the ductility and malleability of Metals. | Metals ductile and malleable in alphabetical order. | Brittle metals in alphabetical order. | Metals in the order of their wire-drawing ductility. | Metals in the order of their laminable ductility. | | Cadmium. | Antimony. | Gold. | Gold. | | Copper. | Arsenic. | Silver. | Silver. | | Gold. | Bismuth. | Platinum. | Copper. | | Iron. | Cerium.? | Iron. | Tin. | | Iridium. | Chromium. | Copper. | Platinum. | | Lead. | Cobalt. | Zinc. | Lead. | | Magnesium. | Columbium.? | Tin. | Zinc. | | Mercury. | Iridium. | Lead. | Iron. | | Nickel. | Manganese. | Nickel. | Nickel. | | Osmium. | Molybdenum. | Palladium.? | Palladium.? | | Palladium. | Osmium. | Cadmium.? | Cadmium.? | | Platinum. | Rhodium. | | | | Pota ium. | Tellurium. | | | | Silver. | Titanium. | | | | Sodium. | Tungsten. | | | | Tin. | Uranium. | | | | Zinc. | | | | There appears to be therefore a real difference between ductility and malleability; for the metals which draw into the finest wire are not those which afford the thinnest leaves under the hammer or in the rolling pre . Of this fact iron affords a good illustration. Among the metals permanent in the air, 17 are ductile and 16 are brittle. But the most ductile cannot be wire-drawn or laminated to any considerable extent without being annealed from time to time during the progre of the extension, or rather, the sliding of the particles alongside of each other, so as to loosen their lateral cohesion.