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.
Whoever imagines he can find the variation within a degree, will very often see himself much deceived. For, besides the imperfection which may be in the construction of the instrument, or in the power of the needle, it is certain that the motion of the ship, or attraction of the ironwork, or some other cause not yet discovered, will frequently occasion far greater errors than this. That the variation may be found, with a share of accuracy more than sufficient to determine the ship’s course, is allowed; but that it can be found so exactly as to fix the longitude within a degree, or sixty miles, I absolutely deny.
CHAP. IV.
THE TWO SHIPS LEAVE THE CAPE OF GOOD HOPE.—TWO ISLANDS, NAMED PRINCE EDWARD’S, SEEN, AND THEIR APPEARANCE DESCRIBED.—KERGUELEN’S LAND VISITED.—ARRIVAL IN CHRISTMAS HARBOUR.—OCCURRENCES THERE.—DESCRIPTION OF IT.
After the disaster which happened to our sheep, it may be well supposed I did not trust those that remained long on shore; but got them, and the other cattle, on board as fast as possible. I also added to my original stock, by purchasing two young bulls, two heifers, two young stone-horses, two mares, two rams, several ewes and goats, and some rabbits and poultry. All of them were intended for New Zealand, Otaheite, and the neighbouring islands, or any other places, in the course of our voyage, where there might be a prospect that the leaving any of them would be useful to posterity.
Towards the latter end of November, the calkers had finished their work on board the Discovery, and she had received all her provisions and water. Of the former, both ships had a supply sufficient for two years and upwards. And every other article we could think of, necessary for such a voyage, that could be had at the Cape, was procured; neither knowing when, or where, we might come to a place where we could furnish ourselves so well.
Having given Captain Clerke a copy of my instructions, and an order directing him how to proceed in case of separation; in the morning of the 30th, we repaired on board. At five in the afternoon, a breeze sprung up at S. E., with which we weighed, and stood out of the bay. At nine it fell calm, and we anchored between Penguin Island and the east shore, where we lay till three o’clock next morning. We then weighed and put to sea, with a light breeze at south; but did not get clear of the land till the morning of the 3d, when with a fresh gale at W. N. W., we stood to the S. E. to get more into the way of these winds.
On the 5th, a sudden squall of wind carried away the Resolution’s mizen top-mast. Having another to replace it, the loss was not felt; especially as it was a bad stick, and had often complained. On the 6th, in the evening, being then in the latitude of 39° 14ʹ S., and in the longitude of 23° 56ʹ E., we passed through several small spots of water of reddish colour. Some of this was taken up; and it was found to abound with a small animal, which the microscope discovered to be like a cray-fish, of a reddish hue.
We continued our course to the south-east, with a very strong gale from the westward, followed by a mountainous sea; which made the ship roll and tumble exceedingly, and gave us a great deal of trouble to preserve the cattle we had on board. Notwithstanding all our care, several goats, especially the males, died; and some sheep. This misfortune was, in a great measure, owing to the cold, which we now began most sensibly to feel.