Another thing that stumbled me here was the variation, which, at this time, by the last amplitude I had found to be but 7 degrees 58 minutes west, whereas the variation at the Cape (from which I found myself not 30 leagues distant) was then computed, and truly, about 11 degrees or more:  and yet a while after this, when I was got 10 leagues to the eastward of the Cape, I found the variation but 10 degrees 40 minutes west, whereas it should have been rather more than at the Cape.  These things, I confess, did puzzle me:  neither was I fully satisfied as to the exactness of the taking the variation at sea:  for in a great sea, which we often meet with, the compass will traverse with the motion of the ship; besides the ship may and will deviate somewhat in steering, even by the best helmsmen:  and then when you come to take an azimuth there is often some difference between him that looks at the compass and the man that takes the altitude height of the sun; and a small error in each, if the error of both should be one way, will make it wide of any great exactness.  But what was most shocking to me, I found that the variation did not always increase or decrease in proportion to the degrees of longitude east or west; as I had a notion they might do to a certain number of degrees of variation east or west, at such or such particular meridians.  But, finding in this voyage that the difference of variation did not bear a regular proportion to the difference of longitude, I was much pleased to see it thus observed in a scheme shown me after my return home, wherein are represented the several variations in the Atlantic Sea, on both sides of the equator, and there the line of no variation in that sea is not a meridian line, but goes very oblique, as do those also which show the increase of variation on each side of it.  In that chart there is so large an advance made as well towards the accounting for those seemingly irregular increases and decreases of variation towards the south-east coast of America as towards the fixing a general scheme or system of the variation everywhere, which would be of such great use in navigation, that I cannot but hope that the ingenious author, Captain Halley, who to his profound skill in all theories of these kinds, hath added and is adding continually personal experiments, will e’er long oblige the world with a fuller discovery of the course of the variation, which hath hitherto been a secret.  For my part I profess myself unqualified for offering at anything of a general scheme; but since matter of fact, and whatever increases the history of the variation, may be of use towards the settling or confirming the theory of it, I shall here once for all insert a table of all the variations I observed beyond the equator in this voyage, both in going out and returning back; and what errors there may be in it I shall leave to be corrected by the observations of others.

(A table of variations.)