The petrel is a bird not much unlike a swallow, but smaller, and with a shorter tail. It is all over black, except a white spot on the rump. They fly sweeping like swallows, and very near the water. They are not so often seen in fair weather; being foul-weather birds, as our seamen call them, and presaging a storm when they come about a ship; who for that reason don't love to see them. In a storm they will hover close under the ship's stern in the wake of the ship (as it is called) or the smoothness which the ship's passing has made on the sea; and there as they fly (gently then) they pat the water alternately with their feet as if they walked upon it; though still upon the wing. And from hence the seamen give them the name of petrels in allusion to St. Peter's walking upon the Lake of Gennesareth.
We also saw many bunches of seaweeds in the latitude of 39 32 and, by judgment near, the meridian of the island Tristan d'Acunha: and then we had about 2 degrees 20 minutes east variation: which was now again decreasing as we ran to the eastward, till near the meridian of Ascension; where we found little or no variation: but from thence, as we ran farther to the east, our variation increased westerly.
OF A BIRD THAT SHOWS THE CAPE OF GOOD HOPE TO BE NEAR: OF THE SEA-RECKONINGS, AND VARIATIONS: AND A TABLE OF ALL THE VARIATIONS OBSERVED IN THIS VOYAGE.
Two days before I made the Cape of Good Hope my variation was 7 degrees 58 minutes west. I was then in 43 degrees 27 minutes east longitude from Cape Salvador, being in latitude 35 degrees 30 minutes, this was the first of June. The second of June I saw a large black fowl, with a whitish flat bill, fly by us; and took great notice of it, because in the East India Waggoner, pilot-book, there is mention made of large fowls, as big as ravens, with white flat bills and black feathers, that fly not above 30 leagues from the Cape, and are looked on as a sign of one's being near it. My reckoning made me then think myself above 90 leagues from the Cape, according to the longitude which the Cape hath in the common sea-charts: so that I was in some doubt whether these were the right fowls spoken of in the Waggoner; or whether those fowls might not fly farther off shore than is there mentioned; or whether, as it proved, I might not be nearer the Cape than I reckoned myself to be; for I found, soon after, that I was not then above 25 or 30 leagues at most from the Cape. Whether the fault were in the charts laying down the Cape too much to the east from Brazil, or were rather in our reckoning, I could not tell: but our reckonings are liable to such uncertainties from steerage, log, currents, half-minute-glasses; and sometimes want of care, as in so long a run cause often a difference of many leagues in the whole account.
Most of my men that kept journals imputed it to the half-minute-glasses: and indeed we had not a good glass in the ship beside the half-watch or two-hour-glasses. As for our half-minute-glasses we tried them all at several times, and we found those that we had used from Brazil as much too short, as others we had used before were too long; which might well make great errors in those several reckonings. A ship ought therefore to have its glasses very exact; and besides, an extraordinary care ought to be used in heaving the log, for fear of giving too much stray line in a moderate gale; and also to stop quickly in a brisk gale, for when a ship runs 8, 9 or 10 knots, half a knot or a knot is soon run out, and not heeded: but to prevent danger, when a man thinks himself near land, the best way is to look out betimes, and lie by in the night, for a commander may err easily himself; beside the errors of those under him, though never so carefully eyed.
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.)
OCCURRENCES NEAR THE CAPE; AND THE AUTHOR'S PASSING BY IT.
But to return from this digression: having fair weather and the winds hanging southerly I jogged on to the eastward to make the Cape. On the third of June we saw a sail to leeward of us, showing English colours. I bore away to speak with her, and found her to be the Antelope of London, commanded by Captain Hammond, and bound for the Bay of Bengal in the service of the New-East-India Company. There were many passengers aboard, going to settle there under Sir Edward Littleton, who was going chief thither: I went aboard and was known by Sir Edward and Mr. Hedges, and kindly received and treated by them and the commander; who had been afraid of us before, though I had sent one of my officers aboard. They had been in at the Cape, and came from thence the day before, having stocked themselves with refreshments. They told me that they were by reckoning 60 miles to the west of the Cape. While I was aboard them a fine small westerly wind sprang up; therefore I shortened my stay with them because I did not design to go in to the Cape. When I took leave I was presented with half a mutton, 12 cabbages, 12 pumpkins, 6 pound of butter, 6 couple of stock-fish, and a quantity of parsnips; sending them some oatmeal which they wanted.
From my first setting out from England I did not design to touch at the Cape; and that was one reason why I touched at Brazil, that there I might refresh my men and prepare them for a long run to New Holland. We had not yet seen the land, but about 2 in the afternoon we saw the Cape land bearing east at about 16 leagues distance: and, Captain Hammond being also bound to double the Cape, we jogged on together this afternoon and the next day, and had several fair sights of it; which may be seen.