32 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



eacli to the moan of the two. The comparisons between Callao and Honolulu show a tine agree- 

 ment from day to day, probably due in part to the almost constant temperatures to which they 

 were exposed. A correction to 1.^89 was obtained, as above explained, and applied in the last 

 column, but for the other chronometers it was found that the corrections would change the result 

 by only 0.2 second, a quantity within the errors of the computation. The adopted values of 

 the longitude are therefore: 



h. m. s. 



10 .59.0, Callao to Honolulu (7 chronometers). 



10 57.1, New York to San Francisco (2 chronometers). 



During the stay upon Caroline Island the Eartford visited Tahiti, where time determinations 

 were made by the navigator of the vessel, which have kindly been furnished, as follows : 



m. s. 



April 30. 233 slow 18 40.22 



1288 fast 5 37.75 



1065 fast - 1 41.70 



425 slow 2 10.65 



The observations were made by equal altitudes with the sextant and I assume for Muta Uta 

 Island, lat, -17° 31' 39" ; long., 149° 34' 21". 



Eeducing these values to April 21 and May 9, by rates determined from the comparisons 

 at Caroline Island on those dates, and comparing with the local corrections (Table lY), we have the 

 following values of the longitude : 



//. in. S. 



L>33 10 52.47 



1288 53.17 



1065 53.05 



425 53.11 



Mean 10 .53.0 



The assumed position of Muta Uta Island is taken from the revised edition of Bowditch 

 Navigator, but its authority and reliability could not be obtained. 



LONGITUDK FROM MOON CULMINATIONS. 



Observations of moon culminations were obtained by Mr. Pkeston on April 25, and 27, 

 and 28. The last, however, cannot be used, as clouds prevented the determination of the posi- 

 tion of the instrument. Three moon-culminating stars were obtained on the tirst night, but clouds 

 interfered with the observations on the second, necessitating the determination of the constants of 

 the instrument by the other stars observed. The computed right ascensions of the moon are as 



follows : 



/». m. s. 

 April 25 17 22 20.09, from m Ophiuchi. 



20.10, from i Ophiuchi. 



20.11, from 58 Ophiuchi. 

 17 22 20.10, mean. 



April 27 19 12 41.,34. 



The resulting longitudes were obtained with the aid of the lunar ephenieris of the American 

 ephemeris and are given below. Through the courtesy of the Superintendent of the United States 



