| Mon. Day, and Year. | Variation. | Difference | Remarks, &c. &c. | |
|---|---|---|---|---|
| 1814 | ||||
| May | ||||
| 11 | 24° 49´ W | Very good sights. | ||
| 12 | 26 18 | — — | ||
| 16 | 21 35 } | 5° 25 | — — | |
| 16 | 27 0 } | — — | ||
| 17 | 27 40 | — — | ||
| 24 | 24 49 | — — | ||
| 25 | 24 4 | — — | ||
| 26 | 20 14 | — — | ||
| Jun | ||||
| 2 | 11 35 | Very good. | Sounded 100 fathoms, fine mud. | |
| 4 | 14 28 | Not very good. | ||
| 8 | 4 55 } | 6 25 | Very good.} | Both sights were equally good. The ship was immediately put on the other tack. |
| 8 | 11 20 } | Very good.} | ||
| 13 | 13 10 | Very good. | North Cape N.W.bW.½W. 5 leagues. | |
| 18 | 16 12 | Very good. | ||
| 26 | 19 6 | Very good. | Ship surrounded with ice. | |
| Jul. | ||||
| 3 | 9 22 | Very good. | ||
| 22 | 16 6 | Very good. | ||
| Aug. | ||||
| 1 | 26 42 | Very good. | Ship some motion. | |
| 2 | 25 14 | Very good. | ||
| 2 | 22 4 } | 7 37 | All these sights were equally good. The evening was remarkablyfine, with a light air from the S.E. The first set was taken with the ship’s head S.S.W.; 2d set at West; and 3d set atN.E.bN. The ship was put round in this manner for the purpose. | |
| 2 | 25 11 } | |||
| 2 | 17 34 } | |||
| 8 | 26 43 | The mean of six sets all good. The weather calm and fine. | ||
| 11 | 31 15 | The mean of two sets ship steady. Longitude obtained by ☉, ☽, and chronometer. | ||
| 14 | 30 36 } | 5 8 | Very good. | |
| 14 | 25 28 } | Very good. | North end of Shetland, S. 11° E. 5 or 6 leagues. | |
| 14 | 30 40 } | 10 25 | Very good. | North end of Shetland, S. 48° W. 4 or 5 leagues. |
| 15 | 20 15 } | Very good. | Outer Skerry, Shetland, S.S.W. 2 miles. | |
| 17 | 30 32 | Very good. | Lamb Head, Orkneys, W.½S. 4 or 5 miles. | |
| Sept. | ||||
| 2 | 33 1 } | 3 30 | Both these sights were good, and the ship was put on the courses,as given purposely. St. Kilda Island S. 9° W. 8 or 9 leagues. No soundings at 180 fathoms. | |
| 2 | 29 31 } | |||
| 13 | 22 30 | At anchor in St. Mary’s. St. Agnes’s Light-House W. 54° S. Castle E. 51° S. | ||
| 14 | 27 16 | This azimuth was taken on shore at St. Agnes’s Light-House, with false horizon. | ||
| 14 | 27 31 | This amplitude was taken on shore at St. Mary’s flag-staff.—Most excellent. | ||
[Transcriber's Note: The table was laid out in the original with the data on one page and the Remarks on the next, this table has been divided to fit the page constraints. The date column has been duplicated and for ease of cross referencing.]
No. IV.
In the Appendix to the second volume of Flinders’ Voyage, which has lately been published, there is an article of considerable length and ability, on the Variation of the Compass. In that article, the observations made by that excellent sailor, corroborate, in a remarkable degree, and accord with those made in the Sybyll. I have selected a few of the most decisive instances.
| 1802. | Lat. | Long. | Course. | Var. | Diff. |
|---|---|---|---|---|---|
| April | |||||
| 22. A.M. | 39° 38´S. | 141° 40´E. az. | W.S.W. | 11° 52´E.} | 3° 53´ |
| 24. | 39 38 | 144 1 | . | 7 59 } | |
| July | |||||
| 15. P.M. | 34 5 | 135 9 | S.E.bE. | 1 33 W.} | 5 39 |
| — | 34 6 | 135 9 ampl. | S.W.bW. | 3 56 E.} | |
| 28. | 25 0 | 153 23 | N.W.bN. | 9 39 } | 3 6 |
| 29. | 24 43 | 153 27 | S.E.½S. | 6 33 } |
After such a coincidence, the fact of the variations depending greatly on the ship’s course cannot possibly be called in question; though it is certainly surprising that it has not been sooner attended to in the way that it deserves, by other navigators; for it did not altogether escape their observations. Mr. Wales, astronomer to Captain Cook’s ship, the Resolution, had made the same observations in a pretty accurate manner; and M. Entrecasteaux, though without assigning any cause, says, that the “Compass showed differences of several degrees in variation at sea, though observed with the greatest care, and within the space of a few minutes.”
After a more enlarged series of observations shall have been taken, and after the attention of astronomers is directed to this fact, we may confidently expect a most important improvement in the science of navigation.