Idealism is native to this temperament, the proper expression of its feeling. Emerson was preordained an idealist; he is one of the eternal men, bearing about him the atmosphere of immortal youth. He is now seventy-three years old, having been born in Boston May 25th, 1803; but his last volume, "Letters and Social Aims," shows the freshness of his first essays. The opening chapter, "Poetry and Imagination," has the emphasis and soaring confidence of undimmed years; and the closing one, "Immortality," sustains an unwearied flight among the agitations of this most hotly-debated of beliefs. The address before the Phi Beta Kappa Society at Cambridge, in 1867, equals in moral grandeur and earnestness of appeal, in faithfulness to ideas and trust in principles, the addresses that made so famous the prime of his career. There is absolutely no abatement of heart or hope; if anything, the tone is richer and more assured than ever it was. During the season of his popularity as a lyceum lecturer, the necessity of making his discourse attractive and entertaining, brought into the foreground the play of his wit, and forced the graver qualities of his mind into partial concealment; but in later years, in the solitude of his study, the undertone of high purpose is heard again, in solemn reverberations, reminding us that the unseen realities are present still; that no opening into the eternal has ever been closed. "Shall we study the mathematics of the sphere," he says to the Cambridge scholars, "and not its causal essence also? Nature is a fable, whose moral blazes through it. There is no use in Copernicus, if the robust periodicity of the solar system does not show its equal perfection in the mental sphere--the periodicity, the compensating errors, the grand reactions. I shall never believe that centrifugence and centripetence balance, unless mind heats and meliorates, as well as the surface and soil of the globe." "On this power, this all-dissolving unity, the emphasis of heaven and earth is laid. Nature is brute, but as this soul quickens it; nature always the effect, mind the flowing cause. Mind carries the law; history is the slow and atomic unfolding." "All vigor is contagious, and when we see creation, we also begin to create. Depth of character, height of genius, can only find nourishment in this soil. The miracles of genius always rest on profound convictions which refuse to be analyzed. Enthusiasm is the leaping lightning, not to be measured by the horse-power of the understanding. Hope never spreads her golden wings but on unfathomable seas."