SOLAR ECLIPSE, MAY 6, 1883. 29 



The correction given by comparison with the Hartford chronometer 1288 rednced to the above 

 time by the rate of 1340 is — 7"' 9».3. Adopting tlie mean — 7'" 10'.3, and deducing the corrections 

 to the other chronometers, we have the corrections already given in Table I. Comparisons with all 

 tlie chronometers of the Hartford were first made on March 24. Carrying forward the correction 

 of 1340 by its assumed rate +0».71, we have the corrections given in Table I on that date. 



It will be seen that the corrections adoi)ted at Callao are uncertain by an amount wliich may 

 reach several seconds. The uncertainties arise from the necessary assumptions made in bringing 

 forward the chronometer corrections, the unreliability of the observation at Aspinwall, and the 

 possible errors in the corrections given for the Hartford chronometer 1288 due to the length of time 

 since observations had been made and to the uncertainty in the longitude of Callao given on chart 

 No. 784, United States Hydrographic Office. In the absence of direct observations at Callao, the 

 corrections adopted are. the best attainable. 



At Honolulu observations with the sextant were attempted both morning and evening for 

 several days after the arrival of t\iQ Hartford. Clouds, however, prevented observations by equal 

 altitudes, but good observations by single altitudes were obtained on three occasions, giving the 

 following corrections to 1340 : 



m. «. 



May 30.392 -8 2.4 



June 1.037 3.0 



June 2.034 4.4 



Mean, May 31.821 -8 3.3 



Reducing to June 1.07G, the time of the nearest chronometer comparisons, we have the correc- 

 tions given in Table I. 



At San Francisco advantage was taken of a time determination made at the observatory of the 

 United States Coast and Geodetic Survey, on the evening after the arrival of the expedition, by 

 Messrs. Edwin Smith and H. S. Pritchett, of the United States Transit of Venus Expedition, 

 through whose courtesy a comparison was made between the chronometers. The resulting correc- 

 tions are given in Table I. 



Determinations of the local time at Caroline Island were made by Mr. Preston with the transit 

 instrument. Previous to the mounting of the instrument, observations with the sextant were made 

 every morning and evening, which were reduced by the method of equal altitudes. The correc- 

 tions in local time to 1340 by these observations were as follows, not including the sextant deter- 

 minations on April 23, a. m., which it was considered unnecessary to use : 



h. h. m. Si. 



April 20, 12 -10 8 33.1 



21, 34.0 



21, 12 34.4 



22, 34.6 



On April 24, 7'', the transit determination of time gave the coiTcction — lO*" 8™ 35'.C7. From 

 these determinations the correction for April 20, 23'', the time of the last comparisons on the Hart- 

 ford before the removal of the chronometers to the shore, was deduced by using the sea rate 



