at least half that time we could think of nothing better to do than sit around the camp-fire on bearskins and talk.  Ever since leaving Petropavlovsk, talking had been our chief amusement; and although it had answered very well for the first hundred nights or so, it was now becoming a little monotonous and our mental resources were running decidedly low.  We could not think of a single subject about which we knew anything that had not been talked over, criticised, and discussed to the very bone.  We had related to each other in detail the whole history of our respective lives, together with the lives of all our ancestors as far back as we knew anything about them.  We had discussed in full every known problem of Love, War, Science, Politics, and Religion, including a great many that we knew nothing whatever about, and had finally been reduced to such topics of conversation as the size of the army with which Xerxes invaded Greece and the probable extent of the Noachian deluge.  As there was no possibility of arriving at any mutually satisfactory conclusion with regard to either of these important questions, the debate had been prolonged for twenty or thirty consecutive nights and the questions finally left open for future consideration.  In cases of desperate emergency, when all other topics of conversation failed, we knew that we could return to Xerxes and the Flood; but these subjects had been dropped by the tacit consent of both parties soon after leaving Gizhiga, and were held in reserve as a “dernier ressort” for stormy nights in Korak yurts.  One night as we were encamped on a great steppe north of Shestakova, the happy idea occurred to me that I might pass away these long evenings out of doors, by delivering a course of lectures to my native drivers upon the wonders of modern science.  It would amuse me and at the same time instruct them—­or at least I hoped it would, and I proceeded at once to put the plan into execution.  I turned my attention first to astronomy.  Camping out on the open steppe, with no roof above except the starry sky, I had every facility for the illustration of my subject, and night after night as we travelled northward I might have been seen in the centre of a group of eager natives, whose swarthy faces were lighted up by the red blaze of the camp-fire, and who listened with childish curiosity while I explained the phenomena of the seasons, the revolution of the planets around the sun, and the causes of a lunar eclipse.  I was compelled, like John Phoenix, to manufacture my own orrery, and I did it with a lump of frozen, tallow to represent the earth, a chunk of black bread for the moon, and small pieces of dried meat for the lesser planets.  The resemblance to the heavenly bodies was not, I must confess, very striking; but by making believe pretty hard we managed to get along.  A spectator would have been amused could he have seen with what grave solemnity I circulated the bread and tallow in their respective orbits, and have heard the long-drawn