Page:A voyage to New Holland - Dampier.djvu/142

 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