130 RECORD OF SCIENCE FOR 1886. 



Prof. W. H. Pickering, of Boston, observing from Fort Green, ob- 

 tained a number of photographs and some interesting photometric 

 observations. He also organized a series of observations of the shadow 

 bands. 



Observations of the partial phase were made at the Azores, Mar- 

 tinique, Port au Prince, and at several points along the eastern coast 

 of the United States. No parties were sent out by the United States 

 Government. 



Photography of the solar corona. — Dr. Huggins's method of photograph- 

 ing the corona in full sunshine seems to have failed when submitted to 

 a crucial test in the eclipse of last August. In a letter to Science, 

 dated September 11, 1886, Dr. .Huggins says: "The partial phases of 

 this eclipse furnished conditions which would put the success of the 

 method beyond doubt if the plates showed the corona cut off partially 

 by the moon during its approach to and passage over the sun. As the 

 telegrams received from Grenada, and a telegram I have received this 

 day from Dr. Gill, at the Cape of Good Hope, state this partial cutting 

 off of the corona by the moon is not shown upon the plates, I wish to 

 be the first to make known this untoward result. I regret greatly that 

 a method which seemed to promise so much new knowledge of the 

 corona, which, under ordinary circumstances of observation, shows it- 

 self only during total eclipses, would seem to have failed. At the same 

 time I am not able to offer any suflficient explanation of the early favor- 

 able results." 



Mr. Common thinks it probable that this failure to get a picture of 

 the moon projected on the corona was due entirely to the state of the 

 sky ; and Professor Langley, in a recent letter to Nature (35 : 53), adds 

 his testimony as to the great effect of atmospheric diffusion upon 'the 

 visibility of the corona. Moreover, Dr. Huggins says that he has not 

 himself been able to obtain any satisfactory results since 1883, and 

 that the plates taken by Mr. Ray Woods in 1884, in Switzerland, are 

 inconclusive. The failure may be due to the abnormally large amount 

 of air-glare from finely divided matter of some sort which has been 

 present in the higher regions of the atmosphere since the autumn of 

 1883. 



It is interesting to note that Professor Wright, of New Haven, in ex- 

 perimenting upon the visibility of the corona, succeeded in obtaining 

 what he believed to be a coronal image upon a screen, when he, too, 

 was brought to a standstill by these same " white skies " and " red 

 sunsets." Professor Wright's method was to admit the sun's rays re- 

 flected from a heliostat, into a darkened room, and to cnt out all but 

 the blue and violet rays by a suitable absorbing cell, and then to form 

 an image of the sun and its surroundings upon a sensitive fluorescent 

 screen, stopping out the sun's disk itself. 



Professor Young seems to have some slight hope of ultimate success 

 of these efforts to reach the corona without an eclipse. 



