The two years that I worked with the Circle of Tchaykóvsky, before I was arrested, left a deep impression upon all my subsequent life and thought. During these two years it was life under high pressure,--that exuberance of life when one feels at every moment the full throbbing of all the fibers of the inner self, and when life is really worth living. I was in a family of men and women so closely united by their common object, and so broadly and delicately humane in their mutual relations, that I cannot now recall a single moment of even temporary friction marring the life of our circle. Those who have had any experience of political agitation will appreciate the value of this statement. Before abandoning entirely my scientific career, I considered myself bound to complete the report of my journey to Finland for the Geographical Society, as well as some other work that I had in hand for the same society; and my new friends were the first to...