RECTIFICATIONS AND ADDITIONS. 453 



RECTIFICATIONS AND ADDITIONS TO THIS VOLUME. 



Pages 3536. 

 See Editor's Note at the foot of p. 36. 



Pages 5556. 



The singular phenomenon of the apparently fluctuating 

 motion of a star has been recently observed again. It was 

 seen by very trustworthy witnesses at Treves, on the 20th of 

 January, 1851, between 7 and 8 in the evening. The star 

 was Sirius, and was near the horizon at the time. See the 

 letter of the Head Master of Mathematics, Herr Mesch, in 

 Jahn's Unterhaltungen fur Preunde der Astronomic. 



Pages 112 and Ik., Note (216). 



The lively wish which I had expressed, to be enabled to 

 trace with more certainty the historical epoch within which 

 the disappearance of the red colour of Sirius falls, has 

 been in part fulfilled by the honourable diligence of a young 

 savant, Dr. Wopcke, who combines great acquaintance 

 with the Oriental languages with distinguished mathe- 

 matical knowledge. This gentleman, the translator of, 

 and commentator on, the important " Algebra" of Omar 



