continuous bands of the corona; while throughout all was discernible a perpetual variability, like the flashing or shooting of colour in the opal, the mother-of-pearl, or similarly tinted translucent substances when exposed to the irregular play of bright light—­only that in this case the tints were incomparably more brilliant, the change more striking, if not more rapid.  I could not say that at any particular moment any point or part of the surface presented this or that definite hue; and yet the general character of the rainbow, suffused with or backed by crimson, was constant and unmistakable.  The light sent through the window was too dim and too imperfectly diffused within my vessel to be serviceable, but for some time I put out the electric lamp in order that its diffused light should not impair my view of this exquisite spectacle.  As thrown, after several reflections, upon the mirror destined afterwards to measure the image of the solar disc, the apparition of the halo was of course much less bright, and its outer boundary ill defined for accurate measurement.  The inner edge, where the light was bounded by the black disc of the Earth, shaded off much more quickly from dark reddish purple into absolute blackness.

And now a surprise, the first I had encountered, awaited me.  I registered the gravity as shown by the barycrite; and, extinguishing the electric lamp, measured repeatedly the semi-diameter of the Earth and of the halo around her upon the discometer, the inner edge of the latter affording the measurement of the black disc, which of itself, of course, cast no reflection.  I saw at once that there was a signal difference in the two indications, and proceeded carefully to revise the earth-measurements.  On the average of thirteen measures the halo was about 87”, or nearly 1-1/2’ in breadth, the disc, allowing for the twilight round its edge or limb, about 2 deg. 50’.  If the refracting atmosphere were some 65 miles in depth, these proportions were correct.  Relighting the lamp, I worked out severally on paper the results indicated by the two instruments.  The discometer gave a distance, roughly speaking, of 40 terrestrial radii, or 160,000 miles.  The barycrite should have shown a gravity, due to the Earth’s attraction, not 40 but 1600 times less than that prevailing on the Earth’s surface; or, to put it in a less accurate form, a weight of 100 lbs. should have weighed an ounce.  It did weigh two ounces, the gravity being not one 1600th but one 800th of terrestrial gravity, or just double what, I expected.  I puzzled myself over this matter longer, probably, than the intelligent reader will do:  the explanation being obvious, like that of many puzzles that bewilder our minds intensely, only to humiliate us proportionately when the solution is found—­a solution as simple as that of Columbus’s egg-riddle.  At length, finding that the lunar angle—­the apparent position of the Moon—­confirmed the reading of the discometer, giving the same apogaic distance or elevation, I supposed that the barycrite must be out of order or subject to some unsuspected law of which future observations might afford evidence and explanation, and turned to other subjects of interest.