for determining the difference of meridians, &e. 93 



M. Largeteau's observations at Fairlight continued. 



VI. Observations made at the top of the Royal Observatory, Greenwich, on the 



rockets at PFrotham. 

 July 11, 1825. The blue light and all the rockets were this evening distinctly seen 

 by the naked eye. The observations were made with telescopes, by three observers, 

 with the same chronometer. The chronometer was compared with the transit clock 

 both before and after observation. The blue light appeared about 9^ 21°* 25'. 



Rockets. 



I 



2 

 3 

 4 

 5 

 6 



7 

 8 



9 



10 



App* Time I. 



9^310.54.48 



9 41 4925 



9 SI 4575 

 10 I 47.5 



10 21 46.75 

 10 31 46.8 



10 51 45.8 



11 I 50.4 



- IL 



54.3' 



49.4 



46.2 



47.8 



45.8 



47-1 

 47.2 

 490 



46.3 

 50.5 



- III. 



- - 54.28 



- - 49-2 



- - 45-8 



- - 47-4 



- - 45-4 

 Absent. 



- - 47-3 



- - 48.4 



- - 46.2 



- - 50.6 



Mean* 



54-30* 

 49.28 

 45.92 



47.56 

 45.60 

 46.92 

 47.10 

 48.70 

 46 10 

 50.50 



*» Mean Error and Rate of Sidereal Clock. 

 Mean of transits of 5 * ' I Corresponding mean error. Rate. 



i6'» 24m I 48.36' — 0.02 



Chronometer fast i" 17.97*. 



The loss of the fifth observation in column I , was occasioned by some accidental derangement of the 

 telescope. The loss of the eighth was occasioned by the rocket passing through the field of view before 

 explosion. Observations 9 and jo, in column i, were made with the naked eye. 



• In taking the mean of the three observations, those marked (: : ) doubtful, are not considered. 



*• The transit observations employed throughout are reduced by the same system of corrections, 

 and mean right ascensions, as those used at the observatory of Paris for that purpose ; so that no error 

 in the results, from a difference of catalogues or corrections, is introduced. 



