F.and solid at--162 deg.

F., temperatures far higher than we should expect to prevail in the polar and north temperate regions of Mars during a considerable part of the year, but such as might be reached there during the summer solstice when the `snows' so rapidly disappear, to be re-formed a few months later.
_The Double Canals._ The curious phenomena of the 'double canals' are undoubtedly the most difficult to explain satisfactorily on any theory that has yet been suggested.

They vary in distance apart from about 100 to 400 miles.

In many cases they appear perfectly parallel, and Mr.Lowell gives us the impression that they are almost always so.

But his maps show, in some cases, decided differences of width at the two extremities, indicating considerable want of parallelism.