THE MYSTERY OF MARS — WILKINS 243 



then in the United States, where Mars was at a much greater altitude, 

 in the southern States over 27 degrees, and advantage was taken of 

 the great American telescopes. Among other instruments the planet 

 was observed with the 60-inch reflector at Mount Wilson Observatory 

 and also with the 40-inch refractor at the Yerkes Observatory; the 

 latter instrument is the largest refracting telescope in the world. 



As seen from Mount Wilson in early June, the ice cap at the south 

 pole was very large and surrounded by a dark band. There is nothing 

 unusual in this, for the melting cap is always seen to be surrounded by 

 a dark band, and the cap was beginning to melt. But what was very 

 unusual was the intense blueness of the markings, more especially the 

 so-called "seas" in the southern hemisphere. Before the cap has appre- 

 ciably contracted these are normally of a grayish hue, and are not 

 pronounced. That this blue color was real was proved by observations 

 with filters of various tints ; the blue came through clearly. There was 

 also a lot of cloud in the atmosphere of Mars, as shown on the drawing 

 on plate 1, which was made with the 60-inch Mount Wilson reflector 

 on June 17. That night only two of the canals could be seen, but it 

 was clear that they were continuous streaks and not made up of a 

 series of dots and dashes. Later on when Mars was examined with 

 the Yerkes 40-inch refractor, numerous canals were detected, and they 

 all appeared to be uniform streaks strongly suggestive of cracks in 

 the surface, while the oases, several of which were seen, suggested 

 craters, presumably filled up with some dark-colored matter. At 

 Yerkes the blue nature of the markings was again evident, almost vivid 

 when contrasted with the reddish regions. They prompted the remark 

 that perhaps Mars too was experiencing unusual weather. It will be 

 remembered that Britain and Europe had a very wet and unsettled 

 summer in 1954. 



With the other and smaller telescopes, such as the 26-inch refractor 

 at the Naval Observatory, Washington, D. C, and the 15^-inch re- 

 fractor at the Washburn Observatory, Madison, the same general re- 

 sults were obtained. At Yerkes the outer moon of Mars, Deimos, was 

 seen close to the planet itself without requiring any shielding of the 

 planet. Even in the great Yerkes telescope this tiny moon appeared 

 as a point of light and not as a disk. Phobos, the inner moon, was 

 always either behind or in front of the planet on the particular occa- 

 sions when I was observing with these magnificent instruments. The 

 clouds persisted, and with the Yerkes instrument a large white one 

 was clearly seen projecting beyond the limb of Mars. 



There have been other attempted explanations of the dark and per- 

 manent markings on Mars. One of the most recent is that of Dr. D. B. 

 McLaughlin, of the University of Michigan, U. S. A. A summary 

 of this new theory was given in the American astronomical journal 



