Evidently the essence of it is control over the human spirit, and the most direct phases of power are immediately spiritual, such as one mind exercises over another by virtue of what it is, without any means but the ordinary symbols of communication. This is live, human power, and those who have it in great degree are the prime movers of society, whether they gain any more formal or conventional sort or not. Such, for instance, are the poets, prophets, philosophers, inventors and men of science of all ages, the great political, military and religious organizers, and even the real captains of industry and commerce. All power involves in its origin mental or spiritual force of some sort; and so far as it attaches to passive attributes, like hereditary social position, offices, bank-accounts, and the like, it does so through the aid of conventions and habits which regard these things as repositories of spiritual force and allow them to exercise its function. In its immediate spiritual phase power is at a maximum of vitality and a minimum of establishment. Only a few can recognize it. Its possessors, then, strive to establish and organize it, to give it social expression and efficacy, to gain position, reputation or wealth. Since power is not apparent to the common mind until it takes on these forms, they are, to superficial observation and in all the conventional business of life, the only valid evidence of it. And yet by the time these symbols appear, the spiritual basis has often passed away. Primary power goes for the most part unseen, much of it taking on no palpable form until late in life, much yielding only posthumous reputation, and much, and that perhaps the finest sort, having never any vulgar recognition whatever.