Decembeb 27, 1907] 



SCIENCE 



911 



the average reader. This calls for neither 

 surprise nor criticism. If it could be demon- 

 strated, beyond reasonable doubt, that in- 

 telligent life, similar to our own, existed on 

 some neighboring world, all men would wish 

 for a time to turn astronomers. 



There are two somewhat distinct problems; 

 first, the determination of the facts so far 

 as that is possible, especially the correct de- 

 lineation of the surface markings, not merely 

 the subjective impression but the objective 

 reality. Second, the interpretation of the ob- 

 served phenom^ena. The first is largely a 

 matter of observation, the second, of specula- 

 tion. Owing to inherent difficulties, it is 

 probable that the observed facts will never be 

 so definite as to exclude a wide range of in- 

 terpretation. 



Some of the difficulties which stand in the 

 way of our knowledge concerning Mars were 

 discussed by Professor Simon Newcomb in 

 the July number of The Astrophysical Jour- 

 nal. According to Professor Newcomb, it is 

 theoretically impossible, owing to instru- 

 mental aberration, to see fine, sharp lines, 

 such as are shown in drawings of Mars, even 

 if they exist on the planet. Various psycho- 

 logical problems also enter into the discus- 

 sion, in addition to physiological ones. Pro- 

 fessor Lowell, in a reply in the October num- 

 ber of the same journal, assails Professor 

 Newcomb's position both from the theoretical 

 and practical side. 



Meanwhile, those observers who do not see 

 the finer details which are shown on the 

 elaborate drawings of the planet have awaited 

 with interest the publication of the photo- 

 graphs, which it is claimed verify them. A 

 display was recently made, at the Massachu- 

 setts Institute of Technology, Boston, of a 

 large number of transparencies, reproduced 

 from the negatives of Mars which were made 

 both in Arizona and in South America. The 

 original negatives, in both places, were ob- 

 tained by the use of a color screen used in 

 connection with special plates. These photo- 

 graphs undoubtedly mark a distinct advance 

 in planetary photography, and much credit is 

 due to Messrs. Lampland and Slipher, Pro- 

 fessor Lowell's assistants. The photographs 



made in Chile excel slightly those obtained 

 earlier in Arizona. All show the broader 

 markings on Mars much better than any ob- 

 tained elsewhere. In a general way they cor- 

 roborate the synchronous drawings by Pro- 

 fessor Lowell. So far as the writer could de- 

 termine, however, from a careful examination 

 of the transparencies, they do not show any of 

 the long, straight, and sharply defined canals 

 shown on many drawings, nor was any trace 

 of doubling visible. It is possible, of course, 

 that groups of fine details, which appear dis- 

 tinct in the brief intervals of good seeing, 

 may be blended on the photograph into the^ 

 broad shadings shown on the transparencies. 

 Though not out of harmony with the draw- 

 ings, it is difficult, nevertheless, to see how the 

 photographs can be regarded as confirming the 

 details. Assuming the drawings to be correct, 

 the photograph even now, compared with the 

 eye, is a very poor second in the delineation 

 of planetary detail. On the other hand, the 

 photographs show nearly as much as has been 

 seen by many conservative observers of Mars. 



Too much importance need not be attached 

 to the doubling of the canals. Whether this 

 is a reality or an illusion does not appear to 

 affect seriously the problem of intelligent life. 

 Even if photographs should be obtained show- 

 ing the canals distinctly double, the objective 

 reality of the phenomenon would not thereby 

 be absolutely assured, that is, photographs 

 like figures sometimes lie. A striking case in 

 point was the announcement, in 1890, by an 

 English astronomer, of a Lyrse as a spectro- 

 scopic binary, from the duplicity of the lines 

 of its spectrum as shown on photographs. 

 This was an error due to causes never ex- 

 plained. This case is unusual only on ac- 

 count of its publicity. An artificial duplicity 

 is one of the ordinary dangers which must 

 be guarded against in astronomical photog- 

 raphy. Sometimes the causes are apparent, at 

 other times they are extremely obscure. 



The subject is one which appeals strongly 

 to the imagination. That intelligent life is 

 confined to our earth alone, out of the many 

 millions of worlds, seems absurd. Whether 

 it exists at the present time on Mars is a fair 

 problem to be decided according to the evi- 



