30 



MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



4-0^835 II]) to the removal, and +0^4:7 after removal, the former being obtained in the coraiiutation 

 later exi)hiined, and the latter the shore rate on Caroline Island. The following are the results : 

 Sextant observations : 



April L'O, 2.5 



h. m. s. 

 ~ 10 8 3;',.48 



3;5.98 



34.15 



34.12 



Mean - 10 8 33.93 



Transit mounted 140 feet west of site of sextant observations : 



h. m. s. 

 Reduction to transit instrument - - - _ - - .09 

 Resulting corr. (from sextant obser- 

 vations) - 10 8 34.02 



Resulting corr. (I'rom transit obser- 

 vations) -10 8 34.00 



Mean - 10 8 34.04 



Upon leaving Caroline Island, the last time determination with the transit Instruraentby Mr. 

 Preston was carried forward by the rate +0^47 to the time of the first comparisons after the 

 return of the chronometers to the Hartford. The computation was as follows : 



7(. VI. It. m. s. 



May 8, 7 49, local time corr. to 1340= -10 8 42.33 

 Red. - .42 



9, 5 



local tinu> 



- 10 8 42.75 



The following table gives the corrections on local mean or sidereal time for each of the nine 

 chronometers before lauding at Caroline Island and immediately upon leaving the island, derived 

 from the chronometer comparisons and using the above corrections for 1340. The times are ex- 

 pressed in Washington mean time to correspond with those in Table I. 



Table IV. — Chronometer corrections at Caroline Island, escpressed in local mean or sidereal time. 



Chronometers 202 and 1589 were altered to local sidereal time for convenience in observations, 

 and were frequently carried about on the island, the latter being used by Mr. Preston in connection 

 with the chronograph. No. 1536 was moved occasionally, and 1340 only once, on the day of the 



