Eclipse Predictions 403 



Column A contains the authority, Nautical Almanac (N. A.) 

 or Connaissance des Temps (C.T.). 



Column B contains the time (G.M.T.) for which each 

 prediction is made. 



Column C contains the calculated distance (in nautical 

 miles) and the bearing of the northern limit of totality from 

 the corresponding southern limit. 



Column D contains the duration of totality on the central 

 line as predicted by the one authority and (in brackets) as 

 interpolated from the prediction of the other. 



Column E contains the differences of these pairs of 

 values. 



It will be seen that, for stations in Spain and the adjacent 

 Mediterranean, the duration of totality on the central line 

 was predicted by the French authority to be from seven to 

 eight seconds longer than by the British authority. In the 

 same region, the width of the band of totality is from ten 

 to eleven nautical miles greater by the French than by the 

 British prediction. The orientation of the line connecting 

 the two limits of totality also differs considerably in the 

 two tables. 



It is reported that at Sousse and Gabes, two towns in 

 Tunisia, the eclipse was partial, while a total eclipse had 

 been predicted for them. The prediction for these places 

 would surely rest on French authority ; we are therefore 

 entitled to conclude that the mistake has been made by the 

 French calculators. An excessive estimate of the width 

 of the band of totality would almost certainly be accom- 

 panied by an excessive estimate of the duration of totality, 

 and the table shows that both estimates are considerably 

 greater in the Connaissance des Temps than in the Nautical 

 A Imanac 1 . 



1 See Contents, p. xxix. 



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