194 



KNOWLEDGE. 



May. 1913. 



in such cases, this statement attracted no attention 

 at the time ; and it was only several years later that 

 it received full confirmation at the hands of Professors 

 Young, Barnard, Hale, and the writer, all observing 

 with very powerful telescopes. And when we 

 recollect that Mr. Denning used in this enquiry only 

 a ten-inch reflector, and that he made his innumer- 

 able other discoveries in an unfavourable climate, 

 and under difficult circumstances, we deem it onlv 



as 



the 



itest of all modern 

 solved bv observation, 



just to consider him 

 observers. 



The canal problem, thus 

 was next approached 

 from the point of view of 

 theory. In 1894-1895, 

 Mr. Maunder laid stress, 

 in these columns, on the 

 errorof believingthat our 

 telescopes reveal to us the 

 ultimate structure of the 

 surface of the planet. 

 As a consequence, he 

 expressed his conviction 

 that the canals are only 

 the summation of a com- 

 plexity of detail, compar- 

 ing them with the linear 

 appearance to the naked 



eye of an irregular stream of sunspots. This is the 

 key to the whole question. " I quite agree with you," 

 says so high an authority as Professor Barnard, in a 

 letter to the writer, " in respect to Mr. Maunder's 



Figure 186. 



Schiaparelli. 

 1883-1884. 



Figure 187. 



The Writer. 

 1909. 



The " Canals " Laestrygon, 

 Antaeus and Tartarus, as seen in 

 an aphelic apparition with an 

 8 J -inch, and in a perihelic appari- 

 tion with a 33-inch Refractor. 



As a patient record of fleeting impressions, his results 

 stand unrivalled ; while his splendid triangulation 

 of the Martian surface has victoriously resisted the 

 test of time. 



An unsympathetic feature of most planetary 

 drawings is the regularity of their markings. 

 Scientific candour is partly responsible for this, as 

 the truthful observer will avoid the impossibility of 

 sketching complex irregularities which he is only 

 glimpsing, rather than introduce elements of doubt 

 in his delineation. A less excusable reason for 

 geometrical outlines may be sought in a widespread 



disregard of angular dia- 

 meters. In fact, areo- 

 graphers too frequently 

 forget that Mars is 

 usually seen as a six- 

 penny piece held at the 

 distance of two feet 

 from the eye ; and 

 that what is sharp on 

 such a small disc, so 

 far off, ought to be 

 represented as exceed- 

 ingly vague on drawings 

 three inches in diameter, 

 seen at the distance of 

 one foot only. 

 The student who passes many consecutive hours 

 in the study of Mars with medium-sized instruments, 

 is liable to catch rare glimpses of straight lines, 

 single or double, generally lasting about one quarter 



Figure 188. 



Schiaparelli. 



1883-1884. 



Figure 189. 



The Writer. 

 1909. 



The "Canal" Eosphoios 

 in an aphelic apparition 

 with an 8J-inch, and in a 

 perihelic apparition with a 

 33-inch Refractor. 



Figure 190. September 18. 



V. Fournier. 



J any Desloges Observatory. 



1 1 J -inch Refractor. 



Figure 191. September 20. 



The Writer. 



Meudon Observatory. 



33 -inch Refractor. 



Figure 192. October 5. 

 From a photograph 

 by Professor Hale. 

 60-inch Refractor. 



Figure 193. November 3. 



Professor Lowell. 



24-inch Refractor, 



stopped down to some 15 inches. 



Views of Syrtis Major and Lacus Moeris in 1909 with various telescopes. 



work in trying to clear up the tangle about the 

 canals of Mars. I think he has thrown much 

 light on the subject." 



Many able observers believed that Schiaparelli 

 had. imagined all his system of spider's webs. But 

 this is quite unfair, as, with the exception of an 

 abuse of magnification, the errors of Schiaparelli 

 were errors of judgment, and not of observation. 

 Although the constant use of high powers made him 

 lose the half-tones of Mars, his outlines of the 

 dusky areas are usually more accurate than anything 

 ever drawn with a telescope of the size he used. 



of a second (see Figures 184 and 185). Here we 

 have a vindication of Schiaparelli's discoveries. 

 But their deceitful character will obtrude itself on 

 the observer using a large telescope, when, in the 

 place of the lines, he will hold steadily, either a 

 winding, knotted, irregular band, or the jagged edge 

 of a half-tone, or some other complex detail (see 

 Figures 186 to 189). 



In their anxiety to prop their views against 

 natural law, believers in the reality of the linear 

 canals have presumed to champion the alleged 

 superiority of small over large telescopes ; and this 



