this circle was a narrow band divided into strips of different length of various colours, each representing one of the peculiar divisions of the Martial day; that point which came under the golden indicator showing the zyda and the exact moment of the zyda, while the movement of the inner circle fixed with equal accuracy the period of day or night.  Below were other circles from which the observer could learn the amount of moisture in the atmosphere, the intensity of the sunlight, and the electric tension at the moment.  Each of the six smaller circles registered on a moving ribbon the indications of every successive moment, these ribbons when unrolled forming a perfect record of temperature, atmospheric pressure, wind, and so forth, in the form of a curve—­a register kept for more than 8000 Martial years.

Four times during the revolution of the great circle each large clock emits for a couple of minutes a species of chime, the nature of which my ignorance of music renders me unable to describe:—­viz., when the line dividing the green and black semicircles is horizontal at noon and midnight, and an hour before, at average sunrise and sunset, it becomes perpendicular.  The individual character of the several chimes, tunes, or peals, whatever they should be called, is so distinct that even I appreciated it.  Further, as the first point of the coloured strip distinguishing each several zyda reaches the golden indicator, a single slightly prolonged sound—­I fancy what is known on Earth as a single chord—­is emitted.  Of these again each is peculiar, so that no one with an ear for music can doubt what is the period of the day announced.  The sound is never, even in the immediate vicinity of the clock, unpleasantly loud; while it penetrates to an amazing distance.  It would be perfectly easy, if needful, to regulate all clocks by mechanical control through the electric network extended all over the face of the planet; but the perfect accuracy of each individual timepiece renders any such check needless.  In those latitudes where day and night during the greater part of the year are not even approximately equal, the black and green semicircles are so enlarged or diminished by mechanical means, that the hour of the day or night is represented as accurately as on the Equator itself.

The examination of this establishment occupied us for two or three hours, and when we remounted our carriage it seemed to me only reasonable that Eveena should be weary both in mind and body.  I proposed, therefore, to return at once, but against this she earnestly protested.

“Well,” I said, “we will finish our excursion, then.  Only remember that whenever you do feel tired you must tell me at once.  I do not know what exertion you can bear, and of course it would be most inconsiderate to measure your endurance by my own.”