Their late arduous wanderings in the keen cold mountain air, with the warmth of the glowing fire and the steaming punch, combined to make Rob drowsy, and ere long he dozed off into a sound sleep; but MacAleister, as he afterwards related, felt in no way able to follow his leader's example, though particularly anxious to do so. He became acutely wakeful, for a strange and unwonted anxiety weighed upon his mind, and at times a shudder passed over his frame--a _grue_, as the Lowlanders term it--a supposed sign that an unseen spirit hovers near you, or that some one is treading on the ground which is to form your grave, however far away that ground may be. His eyes wandered over the old and faded family portraits which adorned the hall; he sought to shun them; but they seemed to exercise a strange fascination over him, which compelled him to look at them again and again, till they grew, to his alarm, almost instinct with life. There was Alaster of Glenstrae, who led the clan to battle at Glenfruin, and who died on the gibbet at Edinburgh, looking grimly out of his iron helmet. There, too, was Colonel Donald MacGregor, in his wig and breastplate, looking as fierce as when he slew Duncan nan Cean, or carried terror among the Westland Whigs when the Highland host came down in the days of the Covenanters. There were others in laced coats and tartan plaids, but all armed to the teeth--worthies who had departed this life with a foot of cold steel in their bodies, leaving more quarrels and broadswords than silver or gold behind them; and as he turned from one pale face to another, while the candles burned down and the fire waxed low on the hearth, MacAleister began to feel how, By dim lights seen, the portraits of the dead Have something ghastly, desolate, and dread! Add to all this the wavering gleams of the fire, the weird shadows they cast across the ancient hall, and the solemn sough of the midnight wind without, as it swept down Glengyle and moaned through the machicolated battlements of the old tower, shaking its grated windows, and waving too and fro the russet-coloured tapestry that overhung the doorway, driving out the brown moths to flutter about the fading lights. Meanwhile Rob Roy slept heavily. By Highland superstition it had long been understood, that when two persons were left thus, they should either both sleep at the same time or keep each other awake; for if one slept, the other was left to the mercy of the spirits of the air. MacAleister called to MacGregor, but received no answer, and in the vaulted hall the hollow echoes of his own voice affrighted even his bold spirit. Then as a sudden and heavy chill fell over his sturdy frame, and a sickly and deadly fear stole into his heart, he strove to rise and grasp his foster-brother, but found himself frozen, riveted, chained, as it were, to his seat by a power or will superior to his own!