Or once again. Suppose that instead of our being on the globe, we were placed in pure space. What time should we find there? No time. We might remain ten years, twenty, a hundred, or a thousand years, but we should never arrive at the next year! In fact each planet makes its own time for its inhabitants, and where there is no planet or anything answering to it there is no time. Jupiter makes for its inhabitants a year which is equal to twelve years of ours, and a day of ten of our hours. Saturn has a year equal to thirty of ours, and days of ten hours and a quarter. In other solar systems there are two or three suns, so that it is difficult to imagine what sort of time they can have. All this infinite diversity of time takes place in eternity, the only thing that is real. The whole history of the earth and its inhabitants takes place, not in time, but in eternity. Before the existence of the earth and our solar system, there was another time, measured by other motions, and having relation to other beings. When the earth shall exist no longer, there may be in the place we now occupy, another time again, for other beings. But they are not realities. A hundred millions of centuries, and a second, have the same real length in eternity. In the middle of space, we could not tell the difference. Our finite minds are not capable of grasping the infinite, and it is well to know that our only idea of time is relative, having relation to the regular events that befall this planet in its course, and not a thing which we can in any way compare with that, which is so alarming to the ideas of some--eternity. We have then to deal with the particular form of time that our planet makes for us, for our personal use. It turns about the sun. An entire circuit forms a period, which we can use for a measure in our terrestrial affairs. We call it a year, or in Latin _annus_, signifying a circle, whence our word _annual_. A second, shorter revolution, turns the earth upon itself, and brings each meridian directly facing the sun, and then round again to the opposite side. This period we call a _day_, from the Latin _dies_, which in Italian becomes _giorne_, whence the French _jour_. In Sanscrit we have the same word in _dyaus_. The length of time that it takes for the earth to arrive at the same position with respect to the stars, which is called a sidereal year, amounts to 365.2563744 days. But during this time, as we have seen, the equinox is displaced among the stars. This secular retrogression brings it each year a little to the east of its former position, so that the sun arrives there about eleven minutes too soon. By taking this amount from the sidereal we obtain the tropical year, which has reference to the seasons and the calendar. Its length is 365.2422166 days, or 365 days, 5 hours, 48 minutes, 47.8 seconds. In what way was the primitive year regulated? was it a solar or a sidereal year?