Cohesion, or Attraction of Cohesion, is that power by which the particles of bodies are held together. The absolute cohesion of solids is measured by the force necessary to tear them asunder; heat is excited at the same time. At the chain cable manufactory of Capt. Brown, a cylindrical bar of iron, of 11/2 inches diameter, was drawn asunder by a force of 43 tons. Before the rupture the bar lengthened about 5 inches, and was reduced nearly three-eighths of an inch at the part where the fracture took place, which became heated to a degree unpleasant, if not painful, to the hand. The cohesive force of metal is considerably increased by hammering, rolling, or drawing. The following table shows the cohesive strength of a square inch in lbs. avoirdupois, or the force necessary to pull asunder a square inch of the various substances named therein.