4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 76 



But it helps very little. Some of these discrepancies are extremely 

 puzzling. 



Take, for example, the total eclipse 1902 X 16. 



Barnard, Yerkes Observatory, air mass c=i.i, reports the darkest 

 eclipse in his experience ; no surface details visible to the naked eye, 

 few with a 6-inch telescope, and those dimly. This report, by itself, 

 would justify a grade of brightness = 0. 



Payne, Northfield, Minn., air mass c=i.2, 5-inch telescope, could 

 easily see all the prominent details of the surface, and recognized 

 many of the lesser ones. This by itself would justify brightness= i. 



O'Halloran, San Francisco, air mass c=i.3, says that the seas 

 and the white streaks so conspicuous at full moon were visible even 

 without magnifying power. 



Godden, London, England, air mass a 4.6 b, could see the seas 

 black as soot, both before and after totality began, with a field glass. 



The last two were experienced amateurs ; their reports agree well 

 enough, and by themselves would justify brightness = 2. 



Taking these four definite reports together, the only possible 

 courses are, a compromise grade =1 (the course adopted) or to 

 reject the reports of the amateurs in favor of Barnard's or Payne's. 

 To do this latter, however, is practically to disqualify amateur evi- 

 dence, which, in the case of many an eclipse, is all the evidence. 



Again, the total eclipse of 1895 IX 3 ; 



Barnard and Perrine, Mt. Hamilton, air mass c=i.5, the main 

 features visible to the naked eye, and easily seen in telescopes of 

 2.5-inch and 12-inch aperture; hence grade = 2. 



Payne and Wilson, Northfield, Minn., air mass b=i.7, at first no 

 markings visible, soon after, many markings in 16-inch, but invisible 

 in 5-inch finder; grade = 0. 



Campos-Roderigues, Lisbon-Tapada, air mass b = 5, with 11. 7 cm. 

 aperture was able to see details, maria and craters, continuously. 

 He says that Aristarchus was notable ; but L. Swift, Echo Mountain, 

 Cal., says that Aristarchus was a very inconspicuous object. 

 Grade = i. 



The amateurs reporting are also in disagreement, as well as the above 

 professionals. The majority of the observers has been allowed to 

 make the grade = 2. 



It will be noted that the discrepancies between Mt. Hamilton and 

 Northfield in the two eclipses are not due to dififerent air masses, 

 these being about the same, and are opposite in sign in the two cases. 



These two instances are not alone ; discrepancies occur of a very 

 puzzling character, and can sometimes be resolved only somewhat 



