Page:The Solar System - Six Lectures - Lowell.djvu/72

 54 . But in the course of his mapping he became aware of some curious markings: dark bands seaming the surface of the light areas, or so-called continents. These he named canali, or channels; for he, in company with every one else, at the time believed the dark regions to be seas.

Having got the hint, for it was scarcely more than that, during his first season, the opposition of 1877, he then showed that element of genius without which very little is ever accomplished, the persistence to follow up a clue. As Mars came round again he attacked the planet in the light of what he had already learnt, and first confirmed and then extended his discovery. This he continued to do at each succeeding opposition. The more he studied, the stranger grew the phenomena he detected. And it is to his everlasting credit that he did this in the face of the skepticism and denial of practically the whole astronomic world. He won. The voices that ridiculed him are all silent now. To-day the canals of Mars are well-recognized astronomic facts, and constitute one of the most epoch-making astronomic discoveries of the nineteenth century.

Through a complete cycle of oppositions, that is, from the nearest to the most remote and round to the nearest again, a period of fifteen years,