seeming permanency of the chief lineaments on Mars, and their
distinctiveness of outline." Schiaparelli confirmed his previous
observations upon the duplications of the canals and Mr. Knobel
published some sketches.

In 1886, M. Terby presented to the Royal Academy of Belgium notes on
drawings made by Herschell and Schroeter, indicating the so-called
Kaiser Sea. M. Perrotin at the Nice Observatory was able to redetect
Schiaparelli's canals, which elicited the remark that "the reality of
the existence of the delicate markings discovered by the keen-sighted
astronomer of Brera seems thus fully demonstrated, and it appears highly
probable that they vary in shape and distinctness with the changes of
the Martial seasons."

These observations of M. Perrotin were detailed at length in the
_Bulletin Astronomique_, and the distinguished observer called attention
to the fact that these markings varied but slightly from Schiaparelli's
chart, and indicated a state of things of considerable stability in the
equatorial region of Mars. M. Perrotin recorded changes in the Kaiser
Sea (Schiaparelli's _Syrtis Major_). This spot, usually dark, was seen
on May 21, 1886, "to be covered with a luminous cloud forming regular
and parallel bands, stretching from northwest to southeast on the
surface, in color somewhat similar to that of the continents but not
quite so bright." These cloud-like coverings were later more distributed
and on the three following days diminished greatly in intensity. They
were referred by Perrotin to clouds.

In March and April of the year 1886 a study was made of the surface of
Mars by W.F. Denning in England. Mr. Denning's drawings corroborated the
charts of Green, Schiaparelli, Knobel, Terby and Baeddicker. He found