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Rh had thus appeared, it continued visible up to the close of the observations sufficiently detailed to show it.

Another curious causeway of the same sort made its appearance in November, connecting the promontory known as Hammonis Cornu with Hellas. Both of these necks of orange-ochre were of more or less uniform breadth throughout.

The long, dark streaks that in June had joined the Syrtis Major to the polar sea had by October nearly disappeared; in their southern parts they had vanished completely, and they had very much faded in their northern ones. The same process of fading uncovered certain curious rhomboidal bright areas in the midst of the Syrtis Major.

It will be seen that the extent of these changes was enormous. Their size, indeed, was only second in importance to their character; for it will also have been noticed that the changes were all in one direction. A wholesale transformation of the blue-green regions into orange-ochre ones was in progress upon that other world.

What can explain so general and so consecutive a change in hue? Water suggests itself; for a vast transference of water from the pole to the equator might account for it. But there are facts connected with the change which seem