1868.] 



President's Address. 



139 



wholly lost in case clouds should prevent observations from being taken 

 at the principal station ; partly because a more rough and general view of the 

 whole phenomenon might reveal features which would be missed in a more 

 careful scrutiny of a particular part. Another telescope, furnished with 

 analyzers for the examination of polarization, was also sent out ; for from 

 the shortness of the time at the disposal of an observer, it would be satisfac- 

 tory that the results obtained, even by so skilful an observer as M. Praz- 

 mouski, should be confirmed. 



The observations of the observers entrusted with these instruments 

 were greatly impeded by flying clouds, notwithstanding which, however, 

 important work was done. With the principal instrument, Lieut. Her- 

 schel ascertained that the spectrum of the prominences showed three 

 isolated bright lines — red, orange, and blue. He had time to take a good 

 measure of the position of the orange line, which proved to be coincident 

 with D, as nearly as the instrument could measure. Clouds prevented the 

 measure of the blue line from being equally good ; it proved, however, to 

 be nearly coincident with P, apparently a very little less refrangible. 

 With one of the hand-spectroscopes Captain Haig, R.E., observed the 

 spectrum of the red jDrominences to consist of two bands, "rose-madder" 

 and " golden yellow," corresponding, doubtless, to the "red" and " orange" 

 of Herschel. But besides these, just before the emergence of the sun, Capt. 

 Haig observed, " in the spectrum of the moon's edge," two well-defined 

 bright bands, one green and one indigo. The seizing of this almost mo- 

 mentary phenomenon, establishing as it does the existence of a thin enve- 

 lope of glowing gas (unless, indeed, the constitution thus revealed were 

 merely local, and its occurrence just at the part of the sun first measured 

 were a mere matter of chance), proves the advantage of not neglecting the 

 use of a comparatively rough instrument intended for a general scrutiny 

 of the phenomenon. 



Of the remaining hand- spectroscopes, one was entrusted to Mr. Cham- 

 bers, Director of the Bombay Observatory, but could not be used on ac- 

 count of clouds, and two were placed in the hands of the commanders of 

 homeward-bound steamers, belonging to the Peninsular and Oriental 

 Steam Navigation Company. Capt. Charles G. Perrins, of the ' Carnatic,' 

 who had charge of one, was unable to apply it to the intended observa- 

 tions, as his ship was about 20 miles north of the track of the total 

 phase ; with the other, Capt. Hennoldson, of the Rangoon,' ascertained 

 the discontinuous character of the red prominences, and his observation 

 would have been very valuable had clouds prevented observations from 

 being taken on shore. 



The telescope furnished with analyzers was placed in the hands of 

 Lieut. Campbell, E.E., who has fully confirmed the previous observation of 

 M. Prazmouski relative to the strong polarization of the light of the 

 corona. 



A feature of the prominences, which is specially noticed in Capt. Haig V 



