A Voyage Towards the South Pole and Round the World (Vol. 1&2). James Cook
Читать онлайн книгу.
we had seen for several days. Indeed they were now so familiar to us, that they were often passed unnoticed; but more generally unseen on account of the thick weather. At nine o'clock in the evening, we came to one, which had a quantity of loose ice about it. As the wind was moderate, and the weather tolerably fair, we shortened sail, and stood on and off, with a view of taking some on board on the return of light. But at four o'clock in the morning, finding ourselves to leeward of this ice, we bore down to an island to leeward of us; there being about it some loose ice, part of which we saw break off. There we brought-to; hoisted out three boats; and in about five or six hours, took up as much ice as yielded fifteen tons of good fresh water. The pieces we took up were hard, and solid as a rock; some of them were so large, that we were obliged to break them with pick- axes before they could be taken into the boats.
The salt water which adhered to the ice, was so trifling as not to be tasted, and, after it had lain on deck for a short time, entirely drained off; and the water which the ice yielded, was perfectly sweet and well- tasted. Part of the ice we broke in pieces, and put into casks; some we melted in the coppers, and filled up the casks with the water; and some we kept on deck for present use. The melting and stowing away the ice is a little tedious, and takes up some time; otherwise this is the most expeditious way of watering I ever met with.
Having got on board this supply of water, and the Adventure about two- thirds as much (of which we stood in great need,) as we had once broke the ice, I did not doubt of getting more whenever we were in want. I therefore without hesitation directed our course more to the south, with a gentle gale at N.W., attended, as usual, with snow showers. In the morning of the 11th, being then in the latitude of 62° 44' S., longitude 37° E., the variation of the compass was 24° 10' W., and the following morning in the latitude of 64° 12' S., longitude 38° 14' E., by the mean of three compasses, it was no more than 23° 52' W. In this situation we saw some penguins; and being near an island of ice from which several pieces had broken, we hoisted out two boats, and took on board as much as filled all our empty casks, and the Adventure did the same. While this was doing, Mr. Forster shot an albatross, whose plumage was of a colour between brown and dark-grey, the head and upper side of the wings rather inclining to black, and it had white eye-brows. We began to see these birds about the time of our first falling in with the ice islands; and some have accompanied us ever since. These, and the dark-brown sort with a yellow bill, were the only albatrosses that had not now forsaken us.
At four o'clock p.m. we hoisted in the boats, and made sail to the S.E., with a gentle breeze at S. by W., attended with showers of snow.
On the 13th, at two o'clock a. m. it fell calm. Of this we took the opportunity to hoist out a boat, to try the current, which we found to set N.W. near one-third of a mile an hour. At the time of trying the current, a Fahrenheit's thermometer was immerged in the sea 100 fathoms below its surface, where it remained twenty minutes. When it came up, the mercury stood at 32, which is the freezing point. Some little time after, being exposed to the surface of the sea, it rose to 33–½, and in the open air to 36. The calm continued till five o'clock in the evening, when it was succeeded by a light breeze from the S. and S.E., with which we stood to the N.E. with all our sails set.
Though the weather continued fair, the sky, as usual, was clouded. However, at nine o'clock the next morning, it was clear; and we were enabled to observe several distances between the sun and moon. The mean result of which gave 39° 30' 30" E. longitude. Mr. Kendal's watch at the same time gave 38° 27' 45" which is 1° 2' 45" W. of the observations; whereas, on the 3d instant, it was half a degree E. of them.
In the evening I found the variation by the mean of azimuths taken with Gregory's compass to be 28° 14' 0"
By the mean of six azimuths by one of Dr
Knight's 28 32 0
And by another of Dr. Knight's 28 34 0
Our latitude at this time was 63° 57', longitude 39° 38–½"
The succeeding morning, the 15th, being then in latitude 63° 33' S., the longitude was observed by the following persons, viz.
Myself, being the mean of six distances of
the sun and moon 40° 1' 45" E.
Mr. Wales, ditto 39 29 45
Ditto, ditto 39 56 45
Lieutenant Clerke, ditto 39 38 0
Mr. Gilbert, ditto 39 48 45
Mr. Smith, ditto 39 18 15—————Mean 39 42 12
Mr. Kendal's watch made 38 41 30
which is nearly the same difference as the day before. But Mr. Wales and I took each of us six distances of the sun and moon, with the telescopes fixed to our sextants, which brought out the longitude nearly the same as the watch.
The results were as follows:—By Mr. Wales, 38° 35' 30", and by me, 38° 36' 45".
It is impossible for me to say whether these or the former are the nearest to the truth; nor can I assign any probable reason for so great a disagreement. We certainly can observe with greater accuracy through the telescope, than with the common sight, when the ship is sufficiently steady. The use of the telescope is found difficult at first, but a little practice will make it familiar. By the assistance of the watch, we shall be able to discover the greatest error this method of observing the longitude at sea is liable to; which at the greatest does not exceed a degree and a half, and in general will be found to be much less. Such is the improvement navigation has received by the astronomers and mathematical instrument- makers of this age; by the former from the valuable tables they have communicated to the public, under the direction of the Board of Longitude, and contained in the astronomical ephemeris; and by the latter, from the great accuracy they observe in making instruments, without which the tables would, in a great measure, lose their effect. The preceding observations were made by four different sextants, of different workmen. Mine was by Mr. Bird; one of Mr. Wales's by Mr. Dollond; the other and Mr. Clerke's by Mr. Ramsden; as also Mr. Gilbert's and Smith's, who observed with the same instrument.
Five tolerably fine days had now succeeded one another. This, besides giving us an opportunity to make the preceding observations, was very serviceable to us on many other accounts, and came at a very seasonable time. For, having on board a good quantity of fresh water, or ice, which was the same thing, the people were enabled to wash and dry their clothes and linen; a care that can never be enough attended to in all long voyages. The winds during this time blew in gentle gales, and the weather was mild. Yet the mercury in the thermometer never rose above 36; and was frequently as low as the freezing point.
In the afternoon having but little wind, I brought-to under an island of ice, and sent a boat to take up some. In the evening the wind freshened at east, and was attended with snow showers and thick hazy weather, which continued great part of the 16th. As we met with little ice, I stood to the south, close hauled; and at six o'clock in the evening, being in the latitude of 64° 56' S., longitude 39° 35' E. I found the variation by Gregory's compass to be 26° 41' W. At this time the motion of the ship was so great that I could by no means observe with any of Dr. Knight's compasses.
As the wind remained invariably fixed at E. and E. by S., I continued to stand to the south; and on the 17th, between eleven and twelve o'clock, we crossed the Antarctic Circle in the longitude of 39° 35' E., for at noon we were by observation in the latitude of 66° 36' 30" S. The weather was now become tolerably clear, so that we could see several leagues round us; and yet we had only seen one island of ice since the morning. But about four p.m. as we were steering to the south, we observed the whole sea in a manner covered with ice, from the direction of S.E., round by the S. to W.
In this space, thirty-eight ice islands, great and small, were seen, besides loose ice in abundance, so that we were obliged to luff for one piece, and bear up for another, and as we continued to advance to the south, it increased in such a manner, that at three quarters past six o'clock, being then in the latitude of 67° 15' S., we could proceed no farther; the ice being entirely closed to the south, in the whole extent from E. to W.S.W., without the least appearance of any opening. This immense field was composed of different kinds of ice; such as high hills, loose