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 }	3° 53´
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.}	5 39
28.	25 0	153 23	N.W.bN.	9 39 }	3 6
29.	24 43	153 27	S.E.½S.	6 33 }	3 6

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.