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



July 19th. The fifth rocket could not be observed. 



Comparison of Chronometer and Clock. 



Chronometer. 

 Before 8" 48-" 

 After II 10 



Clock. 

 16*" 36"" 53.84' 

 18 59 17.02 



Mean Error and Rate of Sidereal Clock. 

 Mean of 3*' I Mean error. | Mean rate. 



1 6*' 50"" 



47.i6« 



— 0.19* 



Comparison from i8th to 19th — 1.81 

 Chronometer fast x™ 16.268 



Observation 10 in columns i and 2 doubtful to half a second. 



