e'las tis'i ty, the property of matter by virtue of which a body is enabled to resume its original form when the outside force by which that form has been changed is removed. Nearly all substances are elastic, but some are much more so than others. Gases are the most elastic, and liquids the least. Hard solids, such as iron, steel and marble, are more elastic than soft ones like dough, putty and lead. Whenever a substance is compressed or extended beyond the limit of its elasticity, it will not resume its former shape. This is often illustrated by rubber bands that have for some time been stretched to a high degree of tension. Such bands lose their elasticity. By compressing gases with a sufficient force, most of them can be changed into liquids. In some instances these liquids return to the gaseous form as soon as the pressure is removed, while in others they do not. The elasticity of tortion, or twisting, illustrated by twisting a cord or wire, is considered the most delicate measure of force and is employed in the most sensitive scientific instruments, such as the galvanometer.