not broad the twelfth part of the diameter of the moon. This planet did appear very black, and her disk very well defined, within the whiteness, which encompassed it about, and whose colour was the same with that of a white crown or halo, of about four or five degrees in diameter, which accompanied it, and had the moon for its centre. ... A little time after the sun had began to appear again, the whiteness and the crown, which did encompass the moon, did entirely vanish."[1] Duillier's comment on this description of the corona is: "The moon's atmosphere cannot well be supposed less than of 130 miles, in perpendicular height. . . . Though it was very plain that the atmosphere of the moon must needs show itself, in the time of a total eclipse of the sun; yet I do not know that anybody did think of this, till in the last month of May, many persons did actually see it."[2]
At Zurich Dr. Scheuchzer, in four lines of Latin, describes how they had a solar eclipse, at once total and annular; total, because the sun was wholly covered by the moon; annular, not properly so called, but by refraction, since around the moon appeared a ruddy brightness (fulgor rutilans), caused by rays refracted through the moon's atmosphere.
The blood-red streak, the corona, the ruddy brightness observed during the total eclipse of 1706, the
- ↑ A letter from a friend at Marseilles informed Duillier that, during totality, "there did remain one bright digit, all about the globe of the moon" (Phil. Trans. (No. 306), p. 2237).
- ↑ "The red prominences were first seen during the solar eclipse of 8th July 1842" (Proctor, Encyc. Brit., vol. ii. p. 788). Baily was not the first to see them. Captain Stannyan and Dr. Scheuchzer carried off the honour 136 years earlier. Facio Duillier has the credit of first describing the corona.
