:.IAY 5, 1899.] 



SCIENCE. 



635 



establish during the oppositions of 1886 

 and 1888 make me very strongly wish that 

 the northern cap could be studied by the 

 observers at Flagstaff with the same suc- 

 cess as the southern. 



A considerable portion of the work is de- 

 voted to the phenomenon which is called, 

 according to usage, the canals of Mars, the 

 nature of which is still entirely obscure, 

 despite the theories, oftentimes pretty and 

 very ingenious, which they have occasioned. 



Mr. Lowell has given a description of 

 these singular formations which seems to 

 me to conform to the truth in the great ma- 

 jority of cases. He has succeeded in show- 

 ing their character quite well in his draw- 

 ings. See plates I, IV, V, VI. If there is 

 any defect here, it is that the differences of 

 the size and intensity of the different canals 

 are not indicated with sufficient clearness. 

 I have had occasion to gain some experi- 

 ence in that line of work, and I have no 

 hesitation in saying that this part of the 

 observations at Flagstaff seems to me to be 

 worthy of the greatest consideration. Be- 

 tween the south pole and the thirtieth par- 

 allel of north latitude (three-quarters of the 

 whole surface of the planet) previous ob- 

 servers have more or less clearly recognized 

 the existence of 70 or 80 canals. At the 

 Lowell Observatory that number has at one 

 stroke been increased to nearly 200, without 

 counting those whose existence could not be 

 satisfactorily verified. The record of ob- 

 servations of these objects made from June 6, 

 1894, to April 3, 1895, occupies no less than 

 85 pages. Frequently 20 or 30 canals could 

 be seen together. In less than an hour, on 

 the night of October 6th, 42 were made out 

 on a portion of the planet which did not 

 amount to a quarter of the whole surface. 

 All three observers took part in the work. 

 The newly discovered canals naturally be- 

 long to the most difflcult class, and a certain 

 number of them have since been verified by 

 two European observers, Leo Brenner at 



Lussinpiecolo and Cerulli at Teramo. I 

 greatly regret that I am unable to add my 

 Own name to those, but my eye no longer 

 has the power necessary for successfully 

 carrying out such difficult observations. 



Several canals were observed in a state 

 of gemination, among others Ganges, 

 Nectar, Euphrates and Phison. On the 

 8th of October Mr. Douglass made the very 

 curious and remarkable observation of the 

 gemination of the Laous SoUs, which seemed 

 to be divided in two by a luminous band on 

 the extension of Nectar. I made a similar 

 observation in 1890, but then the luminous 

 band was on the prolongation of Eosphoros. 

 The same thing is being observed by M. 

 Cerulli at Teramo during the current op- 

 position of 1899. 



As a result of these numerous discoveries 

 and other subsequent ones, as well as future 

 ones, areography is coming to find itself in 

 a condition which may be called an em- 

 barrassment of riches. The network of 

 canals has become so complex that there 

 begins to be considerable difficulty in orient- 

 ing oneself. Imagine three or four hun- 

 dred of these lines traced all together over 

 a globe of but a few seconds of apparent 

 diameter ! The identity of lines seen by 

 different observers at almost the same place 

 is very often doubtful. The difficulty of 

 seeing well and of precisely locating the 

 coordinates of the two extremities may 

 easily give rise to ambiguity and errors. 

 Add to this the frequent changes which the 

 lines undergo in their aspect and their de- 

 gree of visibility ; being now fine and sharp, 

 and again large and diffuse ; sometimes 

 double, often entirely invisible — and one is 

 no longer astonished to see the same line, 

 observed by two different men in a slightly 

 different manner, regarded by them as two 

 distinct objects ; or, on the other hand, to 

 see two essentially different objects con- 

 founded as a single one. The better 

 remedy for avoiding these inconveniences 



