This period, closely accordant with the earth's, is, as far as it goes, another argument for the habitability of Venus.
But now it must be stated that no less eminent an authority than Schiaparelli holds that Venus, as well as Mercury, makes but a single turn on its axis in the course of a revolution about the sun, and, consequently, is a two-faced world, one side staring eternally at the sun and the other side wearing the black mask of endless night.
Schiaparelli made this announcement concerning Venus but a few weeks after publishing his discovery of Mercury's peculiar rotation.

He himself appears to be equally confident in both cases of the correctness of his conclusions and the certainty of his observation.

As with Mercury, several other observers have corroborated him, and particularly Percival Lowell in this country.

Mr.Lowell, indeed, seems unwilling to admit that any doubt can be entertained.

Nevertheless, very grave doubt is entertained, and that by many, and probably by the majority, of the leading professional astronomers and observers.