Circle. 26th Oct. 26 . 13 . 29 20th Oct. P.M.{ 26 . 13 . 58} { 26 . 13 . 47} sext. { 26 . 13 . 57} 22d mean 2 A.M.& 2 P.M. 26 . 13 . 24} circle. 26th 3 P.M. 26 . 13 . 29} Latitude by mean of 3 meridian altitudes 26º. 13'. 39" sextant and circle. mean of 5 altitudes near noon 26 . 13 . 50 sextant. mean of 3 do. do. 26 . 13 . 28 circle. ------------ Mean latitude 26 . 13 . 39 north. * * * * * VARIATION OF THE COMPASS AT NAPAKIANG. The declination of the magnetic meridian was ascertained with considerable precision by means of the transit azimuth instrument: the needle seldom showed the same variation, as it oscillated about ten minutes, but the mean position of the magnetic meridian was 52' 10" west of the true. A coral reef was selected for the place of these observations, in order to avoid the attraction arising from buildings, or from inequalities in the ground. * * * * * _Variation observed on board by Walker's Azimuth Compass._ 29th Sept. 1816, P.M. ship's head W. by S. variation by 1st azimuth 0º. 51'. 30" west. 2nd 0 . 53 . 30 3rd 1 . 17 . 30 Amplitude 1 . 15 . 00 30th A.M. 1st azimuth 0 . 55 . 30 2nd 0 . 34 . 15 3d Oct. A.M. ship's head E.N.E. 1st azimuth 0 . 37 . 00 2nd 0 . 48 . 00 ----------- Variation by mean of 7 azimuths and 1 amplitude 0 . 52 . 39 west. TABLE OF OBSERVATIONS MADE WITH DR. WOLLASTON'S DIP SECTOR: WITH AN ENGRAVING, AND A DESCRIPTION OF THE INSTRUMENT, AND DIRECTIONS FOR ITS USE. [Illustration: Wollaston's Dip Sector] EXPLANATION OF THE DIP SECTOR, AND REMARKS ON THE OBSERVATIONS MADE WITH IT IN HIS MAJESTY'S SLOOP LYRA. In our tables for apparent dip of the visible horizon at different heights from the sea, as calculated from the known curvature of the earth, allowance is made for the refraction of the atmosphere, on a supposition of its being constant, but as it is known to vary, the tabular dip will often be erroneous, and, consequently, altitudes taken under different states of the atmosphere, will exhibit different instead of corresponding results.