"People of Mars" - 1900 Monthly Weather Review Article

Already, in the study of the planet Mars, certain interesting and seemingly anomalous atmospheric conditions have been observed. The insolation of this planet, per unit of area, is less than half that of the earth. This circumstance would seem to imply a rigorous climate, yet it is almost certain that the average temperature at the Martian surface is somewhat higher than that of our own globe; for otherwise we can hardly account for the small extent of the polar snowcaps which are so important a feature of the planet’s topography. . . .

Even could we actually perform the journey to Mars, it is not likely that we would be able to communicate with its inhabitants, and if we found existing there a great number of life forms we would probably have difficulty in deciding to which of them, if any, the designation people should be applied.