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Rh doubts about the moon's atmosphere, and the difficulties experienced in accounting for the crown, "or else concerning a meteor observed, not in our air, but in the vapours that encompass the sun," might have warned Dr. Halley and others to be especially watchful when a total eclipse was due in Britain on April 22, 1715. Halley admitted the points named to be "very singular, and deserving a great deal of attention." He believed that a total eclipse of the sun had not been seen in London since March 20, 1140 A.D. He passes a gentle censure on the French astronomers for their indifference to the total eclipse of 1706, but excuses them on the ground that it was the first which "had been observed with the attention the dignity of the phenomenon requires." Strange to say, he made no preparation to watch for "the blood-streak" and "the luminous ring" that crowned the black body of the moon, when the chance of seeing them again was presented in 1715. They were seen and described by him with a singular turning aside from facts to fables about the moon's atmosphere, and the vapours that were raised or the dews that fell on her surface. Here is the account Halley gives of the red clouds and the luminous ring in the eclipse of 1715: —

"A few seconds before the sun was all hid, there discovered itself round the moon a luminous ring, about a digit, or perhaps a tenth part of the moon's diameter in breadth. It was of a pale whiteness or rather pearl colour, seeming to me a little tinged with the colours of the Iris, and to be concentric with the moon, whence I concluded it the moon's atmosphere. But the great height thereof far exceeding that of our