Rhombic and monoclinic sulphur are two physical states of the element with a transition point at 96°. The relation of amorphous sulphur to liquid sulphur is entirely different. The former is produced by heating liquid sulphur, and is found in increasing proportion as the temperature is raised. At 448° it reaches about forty per cent. As the temperature falls, the proportion of amorphous sulphur recedes, although sudden cooling arrests the regression, and furnishes solid specimens containing the larger proportions proper to higher temperatures. The case seems to be one of chemical equilibrium, S (liquid) ⇌ S (amorphous), in which the action, as written, is endothermal.