The conception of time, the appreciation of duration, are essentially relative to the state of our mind. If we sleep profoundly for seven or eight hours, that time will have made a gap in our life of no greater length than that produced by ten minutes of sleep. The miners who by the collapse of a shaft are entombed for five or six days before being rescued, always believe that they have not been cut off for more than twenty hours. Buried on a Tuesday, for instance, they will not believe that they have had to wait till Sunday. On the other hand, one may seem to pass several hours, very slowly, in a dream of a few seconds. A friend of mine told me that one day, as he was riding through a wood, his horse bolted and threw him into a ravine. He said his fall had certainly not taken more than three seconds, but that during those three seconds he had passed in review at least ten years of his life in all their successive details and without any apparent hurrying of events. Then, again, who has not observed how long the minutes may seem during some hours of waiting? The orbit of the Earth round the Sun being 92 million miles, and that of Saturn 888 million, there are 796 million miles between the two orbits. Light traverses this gap in 70 minutes. My fancy flew this distance with the speed of light, and I was aware of these 2,240 seconds required to cover the distance at the rate of 186,000 miles a second. Yet I am sure that I did not spend all that time in traversing the distance to Saturn, nor even the lesser time corresponding to the distance between Mars and the ringed planet, for the first stroke of ten had sounded on the old clock when I forgot Mars and fixed my attention on Saturn, and I arrived at my destination before the hour had finished striking. I alighted on the tenth satellite, whence one can easily appreciate the grandeur of the Saturnian system. The enormous planet of, a diameter more than 9½ times that of our globe, with a surface 90 times that of the Earth, and a bulk 745 times that of our floating home, is surrounded by gigantic rings measuring 178,000 miles across. Girt by this multiple ring, the planet presides over a retinue of ten satellites revolving round it in a system having a radius of 8 million miles, a system which in itself constitutes a universe larger than that known to the ancients. Until the age of truth inaugurated by the conquests of modern astronomy, nobody on our planet, no poet, no philosopher, no thinker, had guessed the real grandeur of the proportions on which the universe is constructed. How small our Earth appears seen from the Saturnian system! It is barely seen, once in six months, as a small luminous dot near the sun, shining for a few minutes in the evening after sunset, or a few minutes in the morning before sunrise. (4) TWO THOUSAND FIVE HUNDRED MILLION MILES FROM THE SUN