It might be a curious subject to consider how far historical events are modified and the world's destiny affected by the different material agencies which man at various epochs has had at his disposal. The human creature in his passions and ambitions, his sensual or sordid desires, his emotional and moral nature, undergoes less change than might be hoped from age to age. The tyrant; the patriot, the demagogue, the voluptuary, the peasant, the trader, the intriguing politician, the hair-splitting diplomatist, the self-sacrificing martyr, the self-seeking courtier, present essentially one type in the twelfth, the sixteenth, the nineteenth, or any other century. The human tragi-comedy seems ever to repeat itself with the same bustle, with the same excitement for immediate interests, for the development of the instant plot or passing episode, as if the universe began and ended with each generation--as in reality it would appear to do for the great multitude of the actors. There seems but a change of masks, of costume, of phraseology, combined with a noisy but eternal monotony. Yet while men are produced and are whirled away again in endless succession, Man remains, and to all appearance is perpetual and immortal even on this earth. Whatever science acquires man inherits. Whatever steadfastness is gained for great moral truths which change not through the ages--however they may be thought, in dark or falsely brilliant epochs, to resolve themselves into elemental vapour--gives man a securer foothold in his onward and upward progress. The great, continuous history of that progress is not made up of the reigns of kings or the lives of politicians, with whose names history has often found it convenient to mark its epochs. These are but milestones on the turnpike. Human progress is over a vast field, and it is only at considerable intervals that a retrospective view enables us to discern whether the movement has been slow or rapid, onward or retrograde.