names were bestowed, it was supposed that the dark markings really represented water. We have now reason to believe that such is not the case. But it is better to keep the old names, although I shall employ them in a Pickwickian sense, much as we still speak of the Seas of the Moon, the Mare Tranquillitatis, or the Mare Serenitatis, of which only the adjectives have in them anything of truth.
To the west of the Sabaeus Sinus lies another dark, wedge-shaped area, longer than it but single instead of double. This is the Margaritifer Sinus, or the Pearl-bearing Gulf, so named before it was known that that name possessed any significance. But a prescience must have presided over its christening. For we now know that there is indeed a pearl at the bottom of it,—the round spot shown in the picture.
Two lines will be noticed prolonging the twin forks of the Sabaeus Sinus. If we let our look follow down them, we shall mark others and then yet others, and so we might proceed from line to line all over the bright areas of the planet. These lines are the famous canals of Mars. With regard to their surprising symmetry, it is only necessary to say that the better they are seen the more symmetrical they look. Of the two first mentioned, the right-hand one is the Gihon, the left-hand one the Hiddekel,
