LONGITUDE OF SUEZ. 



343 



Mokattam then sent a series of negative signals, which were followed by a 

 negative series from Suez, the whole occupying about one hour. 



From each series there could be obtained three or more comparisons of 

 the chronometers when they were apparently beating together, but as each 

 recorded time was correct within about one-tenth of a second, Captain Browne 

 has preferred to take the mean of all the recorded times, the total number 

 of which is shown in the table (page 345). 



The Solar chronometer employed at Mokattam was compared with the 

 transit-clock before and after each exchange of signals. Stars were observed 

 at both stations on each night, as near as possible to the time of the exchange. 



Captain Browne remarks that the results of the different nights are not so 

 accordant as those obtained in the GREENWICH-MOKATTAM Longitude deter- 

 mination through the immense length of submarine cable, and attributes it 

 to the fact that the instruments used at Suez for the determination and 

 maintenance of local time were not of the high class used at Mokattam. That 

 may be so ; but there is little to complain of. Thanks to the excellence of 

 Captain Browne's arrangements, and the consistent accuracy of Mr. Hunter's 

 work, the Longitude of Suez must be considered to be as satisfactorily 

 determined as that of Mokattam. 



ADOPTED ERRORS and RATES of the SIDEREAL TRANSIT CHRONOMETER LOSEBY 102 



on LOCAL SIDEREAL TIME at SUEZ. 



