Decline of Science in England [31]
the error of level:
Station. Star Latitude Latitude Diffe- by Capt. corrected for rence Sabine error of level.
deg.min.sec. deg.min.sec. sec. Sierra Leone Sirius 8 29 27.9 8 29 34.7 6.8
Ascension Alph.Centuri 7 55 46.7 7 55 40.1 6.6
Bahia Alph.Lyrae 12 59 19.4 12 59 21.4 2.0 Alph.Lyrae 21.2 58 49.8 31.4 Alph.Pavonis 22.4 59 5.1 17.3
Maranham Alph.Lyrae 2 31 42.4 2 31 22 20.4 Alph.Lyrae 43.8 31.8 12.0 Alph.Pavonis 44.5 44 .5 Alph.Lyrae 44.6 42.6 2.0 Alph.Cygni 42.1 39.2 2.9 Alph.Gruris 42.2 27.4 14.8
Trinidad Achernar 10 38 56.1 10 38 58.2 2.1 Alph.Gruris 52.2 50.8 1.4 Achernar 59.3 56.6 2.7
Jamaica Polaris 17 56 8.6 17 56 4.6 4.0 6.6 3.3 3.3
New York Sun 40 42 40.1 40 42 44.6 4.5 Polaris 48.9 38.2 10.7 Sun 41.4 47.2 5.8 Beta Urs.Min. 42.3 58.4 16.1
Hammerfest Sun 70 40 5.3 70 40 7.2 1.9
Spitzbergen Sun 79 49 56.1 79 49 58.6 2.5 Sun 55.9 44.8 11.1 Sun 58.6 52.7 5.9 Sun 59.3 51.6 7.7 Sun 55.8 51.6 4.2 Sun 50 1.5 57.0 4.5
Greenland Sun 74 32 19.9 74 32 32.4 12.4 Sun 17.9 18.7 0.8
Drontheim Sun 63 25 51.3 63 26 6.1 14.8 Alph.Urs.Min. 57.2 49.4 7.8
This presents a very different view of the latitudes as determined by the small repeating circle, from that in Captain Sabine's book; and confining ourselves still to Maranham, where the latitudes "WERE OBTAINED, WITH ESPECIAL REGARD TO EVERY CIRCUMSTANCE BY WHICH THEIR ACCURACY MIGHT BE AFFECTED," and where "A MORE THAN USUAL ATTENTION WAS BESTOWED," it appears, that if we take Captain Sabine's own test, namely, "the differences of the partial results from the mean at each station," the deviations become nearly ten times as large as they were before; a circumstance which might be expected to have some influence in the decision of the question.
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--
Station. Star Latitude Latitude Diffe- by Capt. corrected for rence Sabine error of level.
deg.min.sec. deg.min.sec. sec. Sierra Leone Sirius 8 29 27.9 8 29 34.7 6.8
Ascension Alph.Centuri 7 55 46.7 7 55 40.1 6.6
Bahia Alph.Lyrae 12 59 19.4 12 59 21.4 2.0 Alph.Lyrae 21.2 58 49.8 31.4 Alph.Pavonis 22.4 59 5.1 17.3
Maranham Alph.Lyrae 2 31 42.4 2 31 22 20.4 Alph.Lyrae 43.8 31.8 12.0 Alph.Pavonis 44.5 44 .5 Alph.Lyrae 44.6 42.6 2.0 Alph.Cygni 42.1 39.2 2.9 Alph.Gruris 42.2 27.4 14.8
Trinidad Achernar 10 38 56.1 10 38 58.2 2.1 Alph.Gruris 52.2 50.8 1.4 Achernar 59.3 56.6 2.7
Jamaica Polaris 17 56 8.6 17 56 4.6 4.0 6.6 3.3 3.3
New York Sun 40 42 40.1 40 42 44.6 4.5 Polaris 48.9 38.2 10.7 Sun 41.4 47.2 5.8 Beta Urs.Min. 42.3 58.4 16.1
Hammerfest Sun 70 40 5.3 70 40 7.2 1.9
Spitzbergen Sun 79 49 56.1 79 49 58.6 2.5 Sun 55.9 44.8 11.1 Sun 58.6 52.7 5.9 Sun 59.3 51.6 7.7 Sun 55.8 51.6 4.2 Sun 50 1.5 57.0 4.5
Greenland Sun 74 32 19.9 74 32 32.4 12.4 Sun 17.9 18.7 0.8
Drontheim Sun 63 25 51.3 63 26 6.1 14.8 Alph.Urs.Min. 57.2 49.4 7.8
This presents a very different view of the latitudes as determined by the small repeating circle, from that in Captain Sabine's book; and confining ourselves still to Maranham, where the latitudes "WERE OBTAINED, WITH ESPECIAL REGARD TO EVERY CIRCUMSTANCE BY WHICH THEIR ACCURACY MIGHT BE AFFECTED," and where "A MORE THAN USUAL ATTENTION WAS BESTOWED," it appears, that if we take Captain Sabine's own test, namely, "the differences of the partial results from the mean at each station," the deviations become nearly ten times as large as they were before; a circumstance which might be expected to have some influence in the decision of the question.
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--