446 



NATURE 



[August 29, 1907 



MARS IN 1907. 

 Observations at the Lowell Observatory. 



IN answer to the request of the editor of Nature 

 for an authoritative statement of the observations 

 so far made here at this opposition, I have the honour 

 to communicate two or three of the more important 

 results obtained. They exceed what seemed liliely, in 

 view of the unfavourable declination of the planet, a 

 position so southern as to render it practically un- 

 observable in England, France, or the northern part 

 of the United States. 



The first of these relates to the polar caps. From 

 the fact that the observations were begun in March, 

 three months and a half before opposition, it was 

 possible to catch both caps at an interesting phase of 

 their careers — the southern one at its maximum, the 

 northern at its minimum, extent. The moment was 

 more propitious than has ever been the case before at 

 the times at which the planet has been observed, be- 

 cause it was then upon an even keel as regards the 

 earth, the equator lying nearly in the plane of sight. 

 The southern cap at this epoch stretched across ninety- 

 five degrees of latitude, counting; from one side of it 

 to the other; the northern only over eight. 



From that date the dwindling of the southern cap 

 and the making of the northern has been carefully 

 watched to a complete confirmation of the curious 

 manner in which the latter is formed, as witnessed 

 here at the two previous oppositions.' 



The next point has been the observed development 

 of the canal system in the antarctic and south tem- 

 perate zones. After the melting of the south polar 

 cap had got well under way, canals began to make 

 their appearance about it, running thence down the 

 disc. These canals left its edge and joined the rest 

 of the system in lower latitudes. Connected with such 

 polar phenomena was the appearance of the most 

 southern of the light regions of the planet, Thaumasi.i. 

 This region, lying around the Solis Lacus, or Lake of 

 the Sun, first showed symptoms of awaking activity. 

 The Solis Lacus stood composed of two portions, a 

 large oval patch on the east and a smaller round one 

 to the west ; from both of which canals ran into 

 the dark areas. Now those on the south, such as the 

 .Ambrosia and the Bathys, were darker and more 

 pronounced than those running north, the Tithonius, 

 for example, which showed evidence of being in its 

 dead or skeleton condition, while the former were in 

 full tide of development. Meanwhile, the equatorial 

 canals were steadily fading out. The process of evo- 

 lution was in keeping with the method of development 

 found here for the northern canals in 1903. The 

 fact is of the nature of a prophecy fulfilled, and not 

 only supports the previous observations, but proves the 

 theory deduced from them to have been correct. It 

 1 Sri- Lowell Observatory Bulletin 30. 

 NO. 1974, VOI„ 76] 



is a direct scqnitiir from this that the planet 

 is at present tlie abode of intelligent, constructive 

 life. 



1 may say in this connection that the theory of such 

 life upon Mars wa-. in no way an <i priori hypothesis 

 on my part, but the deduced outcome of observation, 

 and that my observations since have fully confirmed 

 it. No other supposition is consonant with all the 

 facts observed here. 



."Vnother result of this opposition has been the success 

 of the photographs taken of the planet. These have 

 proved delineatory beyond expectation. The increased 

 size of disc has enabled the method worked up by 

 Mr. Lampland to be put into even more effective prac- 

 tice than at the last opposition. Plates have been 

 taken by both Mr. Lampland and myself, and the 

 amount of detail they show may be judged from the 

 facf that I have already counted fifty-si.x canals on my 

 plates, that the twin Gihon has been photographed 

 double, and that such delicate markings as the Fons 

 Juventae and the little canals leading to it appear 

 unmistakably in the prints. Such grosser matters as 

 the dwindling of the southern snow-cap show beauti- 

 fully, and it looks as if a result in which Mr. 

 Crommelin was much interested, the positioning of 

 points of Martian topography by measures of the 

 photographs, was in process of realisation. 



Of the success of the expedition to the Andes to 

 observe and photograph the planet sent out by this 

 observatory under Prof. Todd, and with Mr. E. C. 

 Slipher as the photographer, I prefer to speak later 

 when fuller details come to hand. 

 We already know by cable that their 

 success has been beyond expect- 

 ation. 



Percival Lowell. 



PA' OF. H. C. VOGEL. 

 A STRONOMERS, and especially 

 -'"*- spc'Ctroscopists, will have re- 

 ceived with profound regret the 

 brief announcement from the Pots- 

 (1,'im Observatory which conveyed 

 the sad intelligence that Prof. H. C. 

 Vogcl, the director of that institu- 

 tion, had died on .August 13. 

 His scientific life extends over a period during 

 which all the great triumphs of the spectroscope have 

 been won, and he has been in the front rank of that 

 energetic band of astronomers who have given new 

 direction and increased interest to the science of astro- 

 nomy. Hence to sketch his life would be to trace the 

 history of spectroscopy from the time that Angstrom 

 published the map of the normal spectrum, or from 

 that of the epoch-marking Indian eclipse, when the 

 riddle of the chromosphere was first read ; when the 

 application of the Doppler principle was first applied 

 to star spectra ; or when cometary spectra were first 

 studied. Men's minds were still excited over these 

 novel pursuits, and the possibilities they suggested, 

 when Vogel took charge of the Bothkamp Observ- 

 atory and began that career of continued and successful 

 observation which only terminated with his death. 

 How much has been accomplished since will be ap- 

 preciated if we recall the fact, that Vogel 's earliest 

 work gave us accurate information of the peculiari- 

 ties of the planetary spectra, and showed the 

 effect of solar rotation in displacing the Fraiinhofer 

 lines. 



In 1874 came the foundation of the Potsdam Ob- 

 servatorv, and Prof. Vogel was seen in a new light 

 as the director of the first purely astrophysical ob- 

 servatorv. The staff was small, and the instruments 



