Page:Scientific Monthly, volume 14.djvu/588

 The action of this canal and the rift it seemingly makes in the polar cap corresponds to the observations made by Dr. Lowell and the inferences that he draws from them. He says:

Now the calorific action of vegetation on snow is very often observed on earth and we have seemingly had evidence of the same character upon Mars. If this be so, the two suspected materials—snow and vegetation—on the planet, vouch for each other. The

POLAR RIFTS ON MARS

May 27, 1920.

March 4, 1916. March 9, 1916. February 15, 1918. May 24, 1920.

July 8, 1920. August 2, 1920. August 3, 1920.

May 11, 1920. May 12, 1920.