66 



According to him the double parallax of Arcturus is less 

 than that of a Lyras (the quantity is not stated in Conn, des 

 Tenips.) according to me two seconds. 



According to him « Aquil* has no sensible parallax; ac- 

 cording to me the double parallax is five seconds and an 

 half. 



According to him Procj'on has a considerable double pa- 

 rallax amounting to about QOf' ; according to my observa- 

 tions it has no sensible parallax. 



According to him Sirius has a considerable parallax. This 

 star in this latitude is too much affected by refraction to af- 

 ford any satisfactory conclusion. 



The small changes of zenith distances which I find in 

 a Lyras, in Arcturus and in a Cygni, and from which I con- 

 clude the parallax of each, will, it is not doubted, make 

 astronomers hesitate as to the degree of confidence with 

 which they will receive them. It is not pretended that these 

 quantities can be ascertained to the tenth of a second ; but 

 by continuing the observations, it appears to nic, that I 

 shall at last arrive at that degree of exactness. There seem 

 to be no sources of errors in making these observations, which 

 will not disappear by taking a mean of a great number of 

 observations. However, until my conclusions are supported 

 by other instruments, it is not likely that I shall impress 

 astronomers with the same confidence which I myself pos- 

 sess as to the results. 



