THE SCIENTIFIC WORK OF THE NATIONAL GEOGRAPHIC 

 SOCIETY'S ECLIPSE EXPEDITION TO NORFOLK, VA. 



By Simon Newcomb, LT. D. 



The expeditions spread along the jiatli of total eclipse in the aoees- 

 sible regions over which it swept were so numerous and so well 

 equipped that it was quite unnecessary for the National Geograpliic 

 Society to attempt their work, even had it possessed the means of 

 doing so. Its plan was therefore restricted to a modest attempt 

 to supplement the work of others by such observations as did not 

 require elaborate instrumental means or long previous preparation. 

 The operations finally undertaken were three in number: 



1. Observations of the times of contact and their comparison with 

 prediction. 



2. Photographing the sky during totality, the corona and other 

 surroundings of the sun included, with tiie view of finding any un- 

 known object and of making photometric comparison of the ligh,t of 

 the sky on the disk of the moon with that away from the sun. 



3. Observations of the so-called shadow bands. 



The following imperfect summary of results is all that it is possible 

 to prepare at the present time. 



TIMES OF CONTACTS 



As the oljserver had no optical instrument l)ut a good spyglass, the 

 second and third contacts were the only ones seriously attempted. 

 Such an instrument is as good as a larger one for these contacts. 

 The time was determined by a pocket watch, which was compared 

 with the standard clock at the Naval Observatory^ tlie day before and 

 the day after the eclipse. Tlie corrections of tlie watch to eastern 

 standard time thus determined were: 



.May 27 Corr. = — 28».2 



May 2i) Corr. t: — 2H'.r> 



The correction at the time of tlie eclipse would tiicn 1)0 — 28" 15. It 

 may ha nMnarUed that by a long serii^s of comparisons (lie accidental 

 daily variation of the watch is about ±n\2, and that tlie mean rate 

 during the three weeks before the eclipse cJianci'd to be about zero. 



;i2i 



