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A General History and Collection of Voyages and Travels, Volume 16 eBook

Robert Kerr (writer)
This eBook from the Gutenberg Project consists of approximately 658 pages of information about A General History and Collection of Voyages and Travels, Volume 16.
A.M.\ Observatory           15 deg. 57’ 48-1/2” \
April 4.{      }                   {                    } 15 deg. 49’ 25” East.
\PM  / Mean of four Needles\  15  41   2      /
5. A.M.\  On board the ship      9 deg. 50  49      \
{      }                    {                    } 19  44  47-1/2
6. \P.M./  Mean of four Needles\  19  38  46      /

The variation found on board the ship ought to be taken for the true one; not only as it agreed with what we observed at sea, but because it was found that there was something ashore that had a considerable effect upon the compasses; in some places more than others.  At one spot, on the west point of the Sound, the needle was attracted 113/4 points from its proper direction.

Inclination of the Dipping Needle.

April 5th. Marked \End North \ 71 deg. 26’ 22-12"\
On board with { } } } 71 deg. 40’ 22-1/2”
balanced needle. \Unmarked and dipping 71 54 22-1/2 /

The Same needle    Marked   \End North   \ 72   3  45    \
at the       {           }            }               }  70   0   0
observatory.      \Unmarked and dipping / 71  56  15    /
Marked   \End North   \ 71  58  20    \
18th ditto       {           }            }               }  72   7  15
\Unmarked and dipping / 72  16  10    /
5th.  Spare needle  Marked   \End North   \ 72  32  30    \
at the         {           }            }               }  72  49  15
observatory        \Unmarked and dipping / 73   6   0    /
Marked   \End North   \ 72  55   0    \
18th ditto      {           }            }               }  73  11  45
\Unmarked and dipping / 73  28  30    /
22d.  Spare         Marked   \End North   \ 73  28  38    \
needle on        {           }            }               }  73  11   0
board             \Unmarked and dipping / 72  53  30    /

Hence the mean dip, with both needles, on shore, was 72 32 3-1/4

On board 72 25 45-1/4

This is as near as can be expected; and shews, that whatever it was that affected the compasses, whether on board or ashore, it had no effect upon the dipping needles.

Tides.

It is high water on the days of the new and full moon at 12^h 20^m.  The perpendicular rise and fall, eight feet nine inches; which is to be understood of the day-tides, and those which happen two or three days after the full and new moon.  The night-tides, at this time, rise near two feet higher.  This was very conspicuous during the spring-tide of the full moon, which happened soon after our arrival; and it was obvious, that it would be the same in those of the new moon, though we did not remain here long enough to see the whole of its effect.

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