12 PRESIDENT'S ADDRESS. 



and others on March 25th and 29th. Meteorites, or meteors 

 which reach the surface of the earth without being dissipated 

 by their combustion, have a rather romantic interest, as rare 

 objects coming to us from outside our world, though they do 

 not, I think, contain any substances that are not found on the 

 earth. One which fell in Kentucky on April 9th, 1919, is 

 described as " a meteoric breccia, composed of fragments of 

 two quite dissimilar stones," and it is stated to be so different 

 in character from most meteorites, that unless it had been seen 

 to fall, its meteoric origin would not have been suspected. 

 A new star was discovered in the constellation Cygnus on 

 August 20th last and was afterwards observed on a photo- 

 graphic plate taken on August 16th, though it was absent from 

 one on August 9th. It very quickly reached its maximum 

 brightness of the 2nd magnitude on August 24th, and then 

 quickly declined, being below the 4th magnitude by the end 

 of the month, and the 8th by the end of September. There 

 was nothing unusual about its spectrum. It is now possible to 

 measure the distances apart of the two components of double 

 stars with great accuracy by a device called an interferometer, 

 in which the light passes through two movable slits on to the 

 reflector, which adds much to our knowledge of their relative 

 movements. It has also been found that many of the brightest 

 stars are in a very gaseous condition and consequently of large 

 dimensions. These have been called giant stars, and the 

 denser and smaller ones, dwarfs. The diameter of Betelgeux, 

 one of the brightest stars in Orion, has been calculated to be 

 260,000,000 miles or about 300 times that of the sun, but this 

 being the first calculation of this sort must probably be received 

 with some reserve, though the strides in astronomical instru- 

 ments, methods and knowledge have been immense of late 

 years. In contrast to this I may mention two early Chinese 

 equatorial telescopes constructed in 1279, which were taken 

 by the Germans in 1901, and have, with other early instruments, 

 now been restored to the Chinese. Pictures of these two 

 equatorials are given in Yule's book on Marco Polo, who was 

 in China when they were erected nearly 650 years ago. 



