OF ARTS AND SCIENCES. 361 



search for the suspected phmet, in the event of receiving a negative 

 message from the observer at El-Akhmym, 



The observation at El-Akhmym should also be transmitted to 

 Shanghai (reached by the shadow more than two hours after totality 

 at Teheran), for independent verification at that point. We might 

 thus observe the result of nearly three hours' motion of the planet, — 

 which we might reasonably expect to give important data in regard to 

 its orbit about the sun. Of course, the result of the observations at 

 Teheran would also be transmitted to the observer at Shanghai. 



It was my intention, primarily, to have considered the total eclipse 

 of 1882 merely as an illustration of the method proposed. Further 

 investigation, however, seems to show that it is at least one of the two 

 most favorable eclipses during the present decade, if not during the 

 present century. A few additional considerations merit attention: — 



(1) Accessibility of the observing-stations. El-Akhmym, on the 

 Nile, is only two or three days from Cairo, and nearly the whole jour- 

 ney may be made by rail. By steamer on the Nile, the journey is 

 something like two days longer. Teheran, in so far as I have been 

 able to ascertain, is not difficult of access, though most of the journey 

 must be by caravan-routes, and very little by rail. Of the accessi- 

 bility of Shanghai, nothing need be said. 



(2) Some doubt may exist with regard to the possibility of tele- 

 graphic transmission with sufficient celerity, owing to the necessary 

 number of repetitions of the messages. As for the lines from Egypt 

 to Teheran, and from Egypt to China, the matter will seem less em- 

 barrassed from the fact that these lines are largely under the same 

 control. Three quarters of an hour seems an abundance of time for 

 the transmission of an imperative message from Egypt to Shanghai, 

 allowing five or six repetitions of the message on the way. Of course, 

 the success of the scheme will rest largely with the thoroughness 

 of preconcerted arrangement. The generous courtesy hitherto shown 

 astronomers by the officials in charge of telegraphic lines encourages 

 the belief that they would be disposed to do everything in their power 

 on such an occasion. 



(3) The cloudiness of the stations. The chances of clear weather 

 in Upper Egypt in the middle of May appear to be very good. I 

 have pleasure in thanking Mr. Cleveland Abbe, of the office of the 

 Chief Signal Officer of the Army, for his references in this matter. 

 From observations at Alexandria in the month of May, of the years 

 1870-74, the following results are obtained : — 



