In the account of my last voyage[103], I remarked, that the currents one meets with in this passage generally balance each other. It happened so then; because we crossed the line about 20° more to the eastward than we did now; so that we were, of consequence, longer under the influence of the easterly current, which made up for the westerly one. And this, I apprehend, will generally be the case, if you cross the line 10° or 15° to the east of the meridian of St. Jago. From these remarks I shall draw the following conclusion, that, after passing the Cape de Verde Island, if you do not make above 4° or 5° easting, and cross the line in, or to the westward of, the meridian of St. Jago, you may expect to find your ship 3° or 4° to the westward of her reckoning, by the time you get into the latitude of 10° S. If, on the other hand, you keep well to the east, and cross the line 15° or 20° to the east of St. Jago, you will be then as much to the east of your reckoning; and the more you keep to the eastward, the greater will be your error; as has been experienced by some India ships, whose people have found themselves close upon the coast of Angola, when they thought its distance was above two hundred leagues. During the whole of our passage from England, no opportunity was admitted of observing, with all the attention and accuracy that circumstances would permit, the variation of the compass, which I have inserted in a table, with the latitude and longitude of the ship at the time of observation. As the longitude may be depended upon, to a quarter or half a degree at most, this table will be of use to those navigators who correct their reckoning by the variation. It will also enable Mr. Dun to correct his new Variation Chart, a thing very much wanted. It seems strange to me, that the advocates for the variation should not agree amongst themselves. We find one[104] of them telling us, as I have already observed, _that with 8° west variation, or any thing above that, you may venture to sail by the Cape de Verde Islands, by night or day, being well assured, with that variation, that you are to the eastward of them_. Another, in his chart[105], lays down this variation ninety leagues to the westward of them. Such a disagreement as this, is a strong proof of the uncertainty of both. However, I have no doubt, the former found here, as well as in other places, the variation he mentions. But he should have considered, that at sea, nay even on land, the results of the most accurate observations will not always be the same. Different compasses will give different variations; and even the same compass will differ from itself two degrees, without our being able to discover, much less to remove, the cause.