THE STRANGE MARKINGS ON MARS. 47 



canals of Prof. Schiaparelli, though specially looked for, both 

 during and after the opposition, could not be made out. At the 

 very same time the canals were visible not only to Schiaparelli, 

 but to Perrotin and Terby, and, as we shall see further on, some 

 very remarkable phenomena connected with them were observed. 

 At the Lick Observatory, too, they saw the canals, though they 

 did not perceive all the details and peculiarities noted by Schia- 

 parelli and Perrotin. How shall we account for these remark- 

 able discrepancies ? I do not for a moment think that they shake 

 the . substantial accuracy of the Italian observations. No doubt 

 a clew to the explanation is furnished by what Schiaparelli 

 has recently said of the difficulty of seeing the objects he has 

 described : " On the rare days when these extremely difficult 

 observations are possible, the period of good telescopic images 

 does not last, ordinarily, more than two or three hours during the 

 twilight, or the commencement of night. ... I have found by 

 experience, at Milan, that one can hardly hope to have an at- 

 mosphere sufficiently good during more than eight or ten even- 

 ings (during an opposition) ; sometimes even entire months pass 

 without one's being able to make a satisfactory observation. 

 Much rarer still are evenings of perfect images, those in which 

 one can employ the whole power of an instrument like our Merz 

 equatorial of eighteen inches." 



And this is said of the Italian sky, which has long been famous 

 for the steady views that it gives of the heavenly bodies. What 

 could be expected, then, of the mist-haunted atmosphere of the 

 Potomac flats through which the watchers at our Naval Observa- 

 tory must strain their vision ? At Mount Hamilton they have 

 atmospheric conditions that rival those of Italy, and therefore it 

 was to be foreseen that they could hardly fail to confirm the 

 existence of Schiaparelli's strange markings. 



It should be said, before proceeding, that while the great ma- 

 jority of the canals have been seen only by Schiaparelli himself 

 and a few other observers, there are two or three which had been 

 recognized, though not under their present designation, and per- 

 haps not in their complete extent, before the Italian astronomer 

 made his discovery. Notable among these is the narrow arm 

 running out of the Kaiser Sea, or Syrtis Magna, as Schiaparelli 

 names it, and which he calls the Nilosyrtis. Herschel, and even 

 earlier observers, seem to have noticed this. 



But the detection of the dark lines called canals was only the 

 beginning of Schiaparelli's singular discoveries. The next devel- 

 opment in this remarkable series of observations was the doubling 

 of the canals. Those that he saw in 1877 were simple lines, or 

 narrow bands, and, strange as their appearance was, the liveliest 

 imagination could hardly have prefigured their aspect at subse- 



