94 . Mr. Herschel's account of a series of observations 



July 12. All the signals, the blue light excepted, were this 

 evening visible to the naked eye ; the blue light could not 

 be seen at all :* the times of the explosions w^ere this even- 

 ing all observed with telescopes. 



Rockets. 



App* Time. I 



II. 



Mean. 



: I 



2 



3 



4 



5 



: 6 



7 

 8 



9 



lO 



9631 50' 

 41 50.75 

 51 50.0 



10 1 51.5 

 II 51.8 

 21 53.0 

 31 51.0 

 41 51.2 

 51 48.0 



11 I 49.8 



9»'3i'"49.8» 

 41 50.6 

 51 50.0 



10 I 51.S 

 II 52.2 

 21 52.8 

 31 51.0 



41 51-3 

 51 48.0 



11 I 49.7 



o 



o 



a 



bo 



G 





49.90" 



50.67 



50.00 



51.50 



52.00 



52.90 



51.00 



51.25 



48.C0 



4975 



Chronometer. 



Comparison before 

 After 



9" 11° 

 II 12 



Clock. 



16* 32" 19.94' 

 »8 33 39'8o 



Mean Error and Rate of Transit Clock. 



Mean of 5 • ' I Corresponding error. I Rate. 



16" 24"" I 48.27* I —0.08 



From mean comparison on nth, to ditto on 12th, chronometer gained 1.02'. 

 Chronometer fast i" 18.99'. 



Rockets I and 6 exploded twice, at an interval of about three seconds. The 



first explosion, in each case, was the one observed ; the second, not being expected, 



was lost. 



• None was fired. (H.) 



