The stability of mountain ranges is an equally difficult problem

It is uncertain if they are borne up by the rigidity of the solid material beneath them, or are floating by their levity on a semi-fluid central ma . The results of experiments are thus far indecisive. The amount of deviation of the plumb line from the perpendicular, caused by the ma of the Him a lay as, indicates that these mountains are of le specific gravity than the average crust; and a series of experiments with a pendulum lately made acro N. America give partly similar results. The safest conclusion is probably at present that great mountain ranges are in equilibrium on account of their specific gravity, but that smaller inequalities may in some cases at least be maintained by the rigidity of their material. Mount Crawford, (VA.), BATTLE OF. See PIEDMONT. Mount Desert. Island off coast of Maine, 14 m. by 7; settled by French 1608, by British 1761; summer resort. Pop., 1890, 5,337. Bar Harbor is its chief place.