[31] Not 'of course' because Tycho used it, for, like other able students of science, he made mistakes from time to time. Thus he argued that the earth cannot rotate on her axis, because if she did bodies raised above her surface would be left behind—an argument which even the mechanical knowledge of his own time should have sufficed to invalidate, though it is still used from time to time by paradoxers of our own day.
[32] Chinese chronicles contain other references to new stars. The annals of Ma-touan-lin, which contain the official records of remarkable appearances in the heavens, include some phenomena which manifestly belong to this class. Thus they record that in the year 173 a star appeared between the stars which mark the hind feet of the Centaur. This star remained visible from December in that year until July in the next (about the same time as Tycho Brahe's and Kepler's new stars, presently to be described). Another star, assigned by these annals to the year 1011, seems to be the same as a star referred to by Hepidannus as appearing A.D. 1012. It was of extraordinary brilliancy, and remained visible in the southern part of the heavens during three months. The annals of Ma-touan-lin assign to it a position low down in Sagittarius.
[33] Still a circumstance must be mentioned which tends to show that the star may have been visible a few hours earlier than Dr. Schmidt supposed. Mr. M. Walter, surgeon of the 4th regiment, then stationed in North India, wrote (oddly enough, on May 12, 1867, the first anniversary of Mr. Birmingham's discovery) as follows to Mr. Stone:—'I am certain that this same conflagration was distinctly perceptible here at least six hours earlier. My knowledge of the fact came about in this wise. The night of the 12th of May last year was exceedingly sultry, and about eight o'clock on that evening I got up from the tea-table and rushed into my garden to seek a cooler atmosphere. As my door opens towards the east, the first object that met my view was the Northern Crown. My attention was at once arrested by the sight of a strange star outside the crown' (that is, outside the circlet of stars forming the diadem, not outside the constellation itself). The new star 'was then certainly quite as bright—I rather thought more so—as its neighbour Alphecca,' the chief gem of the crown. 'I was so much struck with its appearance, that I exclaimed to those indoors, "Why, here is a new comet!'" He made a diagram of the constellation, showing the place of the new star correctly. Unfortunately, Mr. Walter does not state why he is so confident, a year after the event, that it was on the 12th of May, and not on the 13th, that he noticed the new star. If he fixed the date only by the star's appearance as a second-magnitude star, his letter proves nothing; for we know that on the 13th it was still shining as brightly as Alphecca, though on the 14th it was perceptibly fainter.
[34] The velocity of three or four miles per second inferred by the elder Struve must now be regarded (as I long since pointed out would prove to be the case) as very far short of the real velocity of our system's motion through stellar space.
[35] M. Cornu's observations are full of interest, and he deserves considerable credit for his energy in availing himself of the few favourable opportunities he had for making them. But he goes beyond his province in adding to his account of them some remarks, intended apparently as a reflection on Mr. Huggins's speculations respecting the star in the Northern Crown. 'I,' says M. Cornu, 'will not try to form any hypothesis about the cause of the outburst. To do so would be unscientific, and such speculations, though interesting, cumber science wofully.' This is sheer nonsense, and comes very ill from an observer whose successes in science have been due entirely to the employment of methods of observation which would have had no existence had others been as unready to think out the meaning of observed facts as he appears to be himself.
[36] The same peculiarity has been noticed since the discovery of the dark ring, the space within that ring being observed by Coolidge and G. Bond at Harvard in 1856 to be apparently darker than the surrounding sky.
[37] I cannot understand why Mr. Webb, in his interesting little work, Celestial Objects for Common Telescopes, says that the satellite theory of the rings certainly seems insufficient to account for the phenomena of the dark ring. It seems, on the contrary, manifest that the dark ring can scarcely be explained in any other way. The observations recently made are altogether inexplicable on any other theory.
[38] A gentleman, whose acquaintance I made in returning from America last spring, assured me that he had found demonstrative evidence showing that a total eclipse of the moon then occurred; for he could prove that Abraham's vision occurred at the time of full moon, so that it could not otherwise have been dark when the sun went down (v. 17). But the horror of great darkness occurred when the sun was going down, and total eclipses of the moon do not behave that way—at least, in our time.
[39] It is not easy to understand what else it could have been. The notion that a conjunction of three planets, which took place shortly before the time of Christ's birth, gave rise to the tradition of the star in the east, though propounded by a former president of the Astronomical Society, could hardly be entertained by an astronomer, unless he entirely rejected Matthew's account, which the author of this theory, being a clergyman, can scarcely have done.
[40] As, for instance, when he makes Homer say of the moon that