To Mrs. Lesley.

Cambridge, Feb. 8, 1870.

I promise myself, if I am very good, that I shall go out to Italy next summer for a short trip, and while I am making final preparations for my lectures. But I ought to keep the promise, perhaps, to myself, since keeping it secret is the only way in which I can be sure of keeping it at all. I imagine that the interest of metaphysics and of travelling will make an agreeable variety. If I find introspection wearisome, I shall have a ready relief at hand, and shall not be in danger of losing my faith in the existence of an external world. If I find so great an extension of externality a bore, I can with profit and without loss of time turn my eyes inward. Isn’t this a generous programme, — an excursion into two worlds at once? The great Kant recommends, for the study of anthropology, in lieu of foreign travels, a residence in some great city, situated on a great river or other thoroughfare of the tide of humanity; and, with an amusing naïveté, — remembering that he was never more than fifty miles away from Königsberg, and considering what must be the travel through that city, — he recommends it as peculiarly fitted for the study of human nature. Perhaps Philadelphia will serve my turn, if Cambridge and the commerce of the Charles have not brought me into sufficient contact with varieties of mankind. Still, Kant

for himself advised rightly; for under his microscope there was doubtless more variety of human nature in his native city than he could, in the distant views of a traveller, have found elsewhere. The naturalist travels only to collect, not to examine, his specimens, unless they are by their very nature spread abroad, as in geology; but if they fly into his museum, all the better: the fatigues and expenses of travel are avoided. But even Kant might have been justified in travelling to visit his friends; and this is a motive which still induces me to hope to see you before many more days.