At length in 1886 Perrotin, at Nice, detected many of Schiaparelli’s canals, and later they were seen by others.  In 1888 Schiaparelli greatly extended his observations, and in 1892 and 1894 some of the canals were studied with the 36-inch telescope of the Lick Observatory, and in the last-named year a very elaborate series of observations upon them was made by Percival Lowell and his associates, Prof.  William C. Pickering and Mr. A.E.  Douglass, at Flagstaff, Arizona.  Mr. Lowell’s charts of the planet are the most complete yet produced, containing 184 canals to which separate names have been given, besides more than a hundred other markings also designated by individual appellations.

It should not be inferred from the fact that Schiaparelli’s discovery in 1877 excited so much surprise and incredulity that no glimpse of the peculiar canal-like markings on Mars had been obtained earlier than that.  At least as long ago as 1864 Mr. Dawes, in England, had seen and sketched half a dozen of the larger canals, or at least the broader parts of them, especially where they connect with the dark regions known as seas, but Dawes did not see them in their full extent, did not recognize their peculiar character, and entirely failed to catch sight of the narrower and more numerous ones which constitute the wonderful network discovered by the Italian astronomer.  Schiaparelli found no less than sixty canals during his first series of observations in 1877.

Let us note some of the more striking facts about the canals which Schiaparelli has described.  We can not do better than quote his own words: 

“There are on this planet, traversing the continents, long dark lines which may be designated as canals, although we do not yet know what they are.  These lines run from one to another of the somber spots that are regarded as seas, and form, over the lighter, or continental, regions a well-defined network.  Their arrangement appears to be invariable and permanent; at least, as far as I can judge from four and a half years of observation.  Nevertheless, their aspect and their degree of visibility are not always the same, and depend upon circumstances which the present state of our knowledge does not yet permit us to explain with certainty.  In 1879 a great number were seen which were not visible in 1877, and in 1882 all those which had been seen at former oppositions were found again, together with new ones.  Sometimes these canals present themselves in the form of shadowy and vague lines, while on other occasions they are clear and precise, like a trace drawn with a pen.  In general they are traced upon the sphere like the lines of great circles; a few show a sensible lateral curvature.  They cross one another obliquely, or at right angles.  They have a breadth of two degrees, or 120 kilometres [74 miles], and several extend over a length of eighty degrees, or 4,800 kilometres [nearly 3,000 miles].  Their tint is very nearly the same as that of the seas, usually a little lighter.  Every canal terminates at both its extremities in a sea, or in another canal; there is not a single example of one coming to an end in the midst of dry land.