The fact that they form a system shows that whatever caused them operated over the whole planet, linked in cause as in effect throughout each section. This at once negatives any purely physical cause of which we have cognizance. For upon a globe still so subject to physical vicissitude as Mars by its aspect shows itself to be, latitude must tell in the phenomena its zones exhibit. Polar snows that wax and wane speak of arctic conditions very diverse from temperate and tropic states, and what would affect the one could not influence the other. Yet the mesh rises superior to zonal solicitation as to local barrier. It is not something dependent either on the temperament or the complexion of the globe’s different parts. It transcends surface restriction and becomes planet-wide in its working. The importance of this omnipresence dilates in meaning as one dwells in thought upon it. Ubiquitous as it is, the mesh which thus covers the Martian surface like a veil spread completely over it, is unlike a veil in being of irregular texture. Not only are the interstices of various shape and pattern, but the mesh itself is of locally differing size. Though the threads are straight and uniform throughout, they are not all alike, besides being unsymmetrically interwoven. Some are at least of ten times the coarseness of others, and from this fact and the bo-peep effect of our air waves all are not visible at once. In consequence the network is not so impressive at first glance as it becomes upon a synthesis of the observations. When this is done, the surface proves to be fairly evenly cut up, as recourse to the maps printed in this volume will amply demonstrate. These maps, as on page 31, are made from the results of but one opposition, and as at each opposition some zone is in a more canal-showing state than others, owing to the Martian season at the time, a still greater uniformity in canal distribution results from a blending of many. From the completeness of the mesh, it follows that in the course taken severally by the canals no one direction preponderates over another. Considered by and large, the canals seem to be equally distributed round the compass points; and this at all longitudes and nearly all latitudes. Tropic, temperate, and even arctic canals show a pleasing impartiality in the matter of the course pursued. The only exceptions occur in the neighborhood of the pole. There a slight tendency may be seen to a north and south setting.