PRESIDENT'S ADDRESS. 11 



the early evening of November 13th. For many years 

 attempts have been made to solve the question of the nature of 

 the zodiacal light by means of its spectrum, but it is so exceed- 

 ingly faint that the subject is attended with great practical 

 difficulties. In 1874 it was in this way shown to be most 

 probably caused by reflected sunlight, and recently fairly 

 successful photographs of the spectrum have been obtained 

 after 12 1 hours' exposure, which confirm this theory. It is 

 supposed that sunlight is reflected from a band of small 

 bodies surrounding the sun. As I mentioned in my Address 

 of last May, it has been practically shown by photographs 

 during an eclipse that no intra-Mercurial planet exists of 

 nearly sufficient size to account for certain observed pertur- 

 bations in Mercury, Venus, the Earth, and Mars, but these 

 might be caused by a number of small bodies such as are 

 supposed to account for the zodiacal light, which tends to 

 confirm this theory as to its nature. A fine Auroral display 

 was seen in England and over the whole route between 

 England and the United States on October 18th last, whereas 

 on September 25th Australia witnessed the finest display 

 of Aurora seen there for 50 years. Definite proof is now forth- 

 coming that new canals are being formed in Mars, in addition 

 to those already known, the new ones being too conspicuous 

 to admit of their having been overlooked during all the years 

 in which Mars has been under special observation for this 

 phenomenon. In 1907 it was considered to be certainly, 

 proved that water existed in Mars, and it is now proved 

 that free oxygen also exists there. The difficulty is that 

 the spectroscope does not discriminate between water and 

 other things in suspension in our atmosphere and in that 

 of Mars, the ray of light from Mars having to pass through 

 both, but recently, by photographing and comparing the 

 spectra of Mars and the Moon, taken at the same time, it 

 has been shown that the atmosphere of Mars contains more 

 oxygen than that of the Moon, that in our atmosphere 

 being the same of course in both spectra. Curiously, 

 on this occasion, no water could be traced in Mars, but this 



