and the air and the deep--has ever been one of the same peril which an invader must brave when he crosses the bounds of his nation. By this key alone you unlock all the cells of the alchemist's lore; by this alone understand how a labor, which a chemist's crudest apprentice could perform, has baffled the giant fathers of all your dwarfed children of science. Nature, that stores this priceless boon, seems to shrink from conceding it to man--the invisible tribes that abhor him oppose themselves to the gain that might give them a master. The duller of those who were the life-seekers of old would have told you how some chance, trivial, unlooked-for, foiled their grand hope at the very point of fruition; some doltish mistake, some improvident oversight, a defect in the sulphur, a wild overflow in the quicksilver, or a flaw in the bellows, or a pupil who failed to replenish the fuel, by falling asleep by the furnace. The invisible foes seldom vouchsafe to make themselves visible where they can frustrate the bungler as they mock at his toils from their ambush. But the mightier adventurers, equally foiled in despite of their patience and skill, would have said, 'Not with us rests the fault; we neglected no caution, we failed from no oversight. But out from the caldron dread faces arose, and the specters or demons dismayed and baffled us.' Such, then, is the danger which seems so appalling to a son of the East, as it seemed to a seer in the dark age of Europe. But we can deride all its threats, you and I. For myself, I own frankly I take all the safety that the charms and resources of magic bestow. You, for your safety, have the cultured and disciplined reason which reduces all fantasies to nervous impressions; and I rely on the courage of one who has questioned, unquailing, the Luminous Shadow, and wrested from the hand of the magician himself the wand which concentered the wonders of will!" To this strange and long discourse I listened without interruption, and now quietly answered: