being converted into the instruments and evidences of peace.
There are many other branches of the subject upon which I should like to have dwelt to-day, but which I have not here the time to examine. Such are the reciprocal influence of Fortifications upon Frontiers, and of Frontiers upon Fortifications; the effect upon Frontiers of modern scientific inventions, such as the electric telegraph, railroads and tunnels, and munitions of war; the experience and romance of Frontier Commissions. There is also a class of so-called Natural Frontiers which I have been obliged to omit, as possessing no valid claim to the title, namely those which are claimed by nations as natural on grounds of ambition, or expediency, or more often sentiment. The attempt to realize Frontiers of this type has been responsible for many of the wars, and some of the most tragical vicissitudes in history. But its treatment would almost demand an independent Essay. When I began to write this lecture I had further contemplated tracing the comparative evolution of the Frontiers of all the great Empires in history, giving an exact account of the Indian Frontier system, at present the most highly organized in the world, and comparing it point by point with its ancient counterpart and prototype, the Frontier system of Rome. These designs must be postponed for a larger work on the same subject, if the leisure for this be ever found. Another deferred topic is the engrossing subject of Border Literature, in which it would, I believe, be possible to demonstrate a common growth and characterization in diverse periods and many lands. I should also like to have analysed the types of manhood thrown up by Frontier life, savage, chivalrous, desperate, adven-
