THE PLANET MERCURY.

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sented recalled the appellation— 6 2tCx/3(ov, the glittering , orsparkling one, given to it by the ancient Greeks.

The telescope has, however, revealed its phases, and hasenabled us to detect and watch it when in transit. But, other-wise, it has taught us very little of importance, or of interest,with regard to it. Mercury is a disappointing and difficulttelescopic object. It is hard to get a well-defined and distinctview of its disc. Its very considerable distance from the Earth ,when otherwise most favourably placed for observation ; itscomparatively small size ; the intense brightness of its light;the solar glare that surrounds it; and some inherent peculiarityof its surface, or of its atmospheric envelope ;—all combine torender our telescopic observations disappointing.

It is true that, near to the end of the last century, Schroterbelieved that a high mountain was periodically visible as aninequality in the boundary of the illuminated portion of its disc;and that he saw a belt probably equatoreal, and indicating anaxis tilted at about 70° * to the plane of its orbit (an inclinationvery similar to that of the Earth ’s axis), during a period of 47days in May and June 1801. But we believe that the carefulobservations of Sir W. Herschel did not confirm these state-ments ; while most modern astronomers have felt it uselessto devote much time to this planet. Indeed, we are almostforced to suppose that if Schroter was not deceived as to whathe saw fa remark which may, in some degree, also apply tohis, and some other, observations of Venus made a generation ortwo ago) the atmosphere, or cloudy envelope of Mercury , must

* We have tried in vain to meet with a copy of Schroter’s “ Hermo-graphische Fragmente ” in several English libraries. By the kindness ofM. Niesten, of the Brussels Observatory, in which the book is to be found,we have, however, obtained a copy of Schroter’s original statement, andwe are Surprised to notice that in almost every English book (except inDr. Ball’s recent quotation of Houzeau’s astronomical constants in his“ Elements of Astronomy,” published in the Science Text-Book Series)the complement of Schroter's angle of about 70",— i.e., an angle of about20°,—is given in place of the inclination of the axis really stated by him.Very erroneous deductions have consequently been made as to the seasonsand climatic zones which Schroter's value would involve. They wouldreally be, according to him, in close agreement with those of the Earth

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