observations a few days afterward [MONDAY 27] with every compass on board, and Mr. Thistle did the same upon the booms, ten or twelve feet before the main mast, where the compasses were as far removed from any quantity of iron, as they could be placed in any part of the ship.  The head was south-west by the steering compass, our latitude was 38 deg. 1’ north, longitude 14 deg. 18’ west, and the results were as under.

Binnacle.  Booms. 
Variation from an azimuth compass by Walker, deg. ’ deg. ’ marked No 1:  mean of both sides of the vane. 25 47 22 17 W. From a ditto marked No. 2, 25 35 19 15
ditto marked No. 3, 24 41 21 27
Walker’s meridional compass, 25 46 — —
Ditto used as a common azimuth, 25 51 20 35
Compass made by Adams, 25 44 21 9
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Means, 25 34 20 57 W.
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Thus a change of place from the binnacle to a little before the centre of the ship, produced an alteration of 4 deg. 37’ in the mean variation, the same way as, but a less quantity than Mr. Thistle had found it off the Start, when the ship’s head was west.  The true variation I judge to have been 23 deg., and that the observations on the booms showed 2 deg. too little, and those on the binnacle 21/2 deg. too much.  The error in excess, upon the binnacle, appeared to continue so long as the ship was in the northern hemisphere and the head to the westward; but it diminished gradually as we approached the equator, and the observations on the binnacle and booms then nearly coincided.  This example is sufficient to show the impropriety of allowing a variation upon the ship’s course, from observations taken elsewhere than at the binnacle.

THURSDAY 30 JULY 1801.

We continued our course for Madeira, with fair winds.  Our latitude on the 30th, was 30 deg. 5’ north, longitude 15 deg. 31’ west; and in the afternoon Porto Santo was seen, bearing west-north-west; the wind then became light and variable, and soon afterwards died away.  The variation observed on the binnacle by the master, when the head was south-west-by-south, was 22 deg. 45’, but on the booms 19 deg. 51’; the true variation being as I believe, 20 deg. 51’ west.

FRIDAY 31 JULY 1801.

It was calm on the 31st, and I had a boat lowered down and went round the ship with the carpenter, to inspect the seams near the water line, for we had the mortification to find the ship beginning to leak so soon as the channel was cleared, and in the three last days she had admitted three inches of water per hour.  The seams appeared sufficiently bad, especially under the counter and at the butt ends, for the leak to be attributable to them; and as less water came in when the ship was upright than when heeling to a beam wind, I hoped the cause need not be sought lower down.  Before hoisting up the boat, a small hawke’s-bill turtle was picked up; and between this time and that of anchoring in Funchal Road, several others were seen, and a second, weighing about thirty pounds, was caught.