There is, however, another light in which it is impossible to avoid looking at this singular oversight. The second column of the table of latitudes must now be considered the true one, as that which really resulted from the observations. Now, on examining the column of true latitudes, the differences between the different sets of observations is so considerable as naturally to excite some fear of latent error, more especially as nearly the greatest discordance arises from the same star, Alph.Lyrae, observed after an interval of only three days. It becomes interesting to every person engaged in making astronomical observations, to know what is the probability of his being exposed to an error so little to be guarded against, and so calculated to lull the suspicions of the unfortunate astronomer to whom it may happen. In fact, the question resolves itself into this: the true latitude of a place being determined by sets of observations as in the first of the following columns-- Latitudes as True latitudes observed. computed by a mistake of Capt. Sabine's. deg.min.sec. deg.min.sec. Alph.Lyrae, 28th Aug.... 2 31 22.0 2 31 42.4 Alph.Lyrae, 29th Aug.... 31.8 43.8 Alph.Pavonis, 29th Aug... 44,0 44.5 Alph.Lyrae, 31st Aug.... 42.6 44.6 Alph.Cygni, 31st Aug.... 39.2 42.0 Alph.Gruris, 2d Sept.... 27.4 42.2 what are the chances that, by one error all the latitudes in the first column should be brought so nearly to an agreement as they are in the second column? The circumstance of the number of divisions of the level being almost arbitrary within limits, might perhaps be alleged as diminishing this extraordinary improbability: but let any one consider, if he choose the error of each set, as independent of the others, still he will find the odds against it enormous. When it is considered that an error, almost arbitrary in its law, has thus had the effect of bringing discordant observations into an almost unprecedented accordance, as at Maranham; and not merely so, but that at eight of the nine stations it has uniformly tended to diminish the differences between the partial results, and that at the ninth station it only increased it by a small fraction of a second, I cannot help feeling that it is more probable even that Captain Kater, with all his admitted skill, and that Captain Sabine himself, should have been both mistaken in their measures of the divisions of the level, than that so singular an effect should have been produced by one error; and I cannot bring myself to believe that such an anticipation is entirely without foundation.