ON THE DETERMINATION OF TRANSATLANTIC LONGITUDES. 



459 



DIFFERENCE OF LONGITUDE BETWEEN 



Kind of Signal. 



Sidereal 

 Clocks. 



Key or 

 Hand-signals. 



Cable-Key at 

 Duxbury and 

 M. T. clock at 



Cambridge. 



SIGNALS SENT IN BOTH DIRECTIONS. 



AND DUXBURY, FROM 



Date. 



<( 



«< 



Dec. 14 



15 



23 



31 



3 



4 



u 



Jan 



«< 



Dec. 15 



23 



31 



3 



a 



a 



Jan. 



Jan. 14 



22 

 24 

 26 

 28 

 9 

 10 



U 



U 



u 



u 



Feb 



a 



x 



x 



110.294 

 110.307 

 110.437 

 110.396 



110.258 

 110.112 



s 



110.362 

 110.475 

 110.419 

 110.269 



8 



111.176 

 110.512 

 110.619 

 110.274 

 110.325 

 110.761 

 110.490 



X + x 



110.381 

 110.392 

 110.541 

 110.449 

 110.303 



110.378 

 110.509 

 110.430 

 110.288 



110.530 

 110.653 

 110.284 

 110.338 

 110.785 

 110.502 



x 



0.044 

 0.042 

 0.052 

 0.027 

 0.022 

 0.037 



I 



1 1 ( 1.337 

 1 1 0.350 

 110.489 

 110.422 



1 10.281 



110.149 



0.008 



110.370 



0.017 



110.4 ( .>2 



0.006 



110.425 



0.009 



110.278 



o!o09 



11U85 



0.009 



110.521 



0.017 



110.636 



0.005 



110.279 



0.007 



110.S81 



0.012 



110.773 



0.006 



110.496 



On January 14, 22, and 24, and on February 9, the time at one or both of the stations was computed from 

 the error and rate of the clocks obtained on other nights, in most cases two or three days intervening. The 

 clock-rates were not constant, and the results, therefore, are not trustworthy. On January 4, the clock error 

 at Cambridge was found from poor observations on only two stars. In the following table the observations on 

 all these nights are rejected. 



" 15 



« 23 



" 31 



Jan. 3 



26 

 28 

 10 



.. 



u 





110.294 

 110.334 

 110.456 

 110.407 

 110.263 

 110.274 

 110.325 

 110.490 



110.381 

 110.385 

 110.525 

 110.440 

 110.296 

 110.284 

 110.338 

 110.502 



Mean of 1672 signals 





X 



x 



0.044 

 0.025 

 0.034 

 0.016 

 0.016 

 0.005 

 0.007 

 0.006 



110'.375 

 ±.021 



The correction for the difference of the Personal Equation in taking transits between 

 Mr. Good fellow and Mr. Austin is 



X 



110.337 

 110.360 

 110.490 



110.423 

 110.280 

 110.279 

 110.331 

 110.496 



Applying this correction we have 

 * the difference of Longitude between Duxbury and Ca 

 Difference of Longitude between Brest and Duxbury 

 Difference of Longitude between Brest and Cambridge 



X 



0U45 ± .007 

 h l m 50\230 ± .022 



4 h 24™ 42'.867 ± .047 

 4 h 26™ 33'.097 ± .052 



