A VOYAGE ROUND THE WORLD.
95
1772.
December.
have been formed in the sea[1]; an idea the more probable, as repeated and decisive experiments have evinced, that salt-water may be frozen.
This ice likewise served to shew us the great difference between the temperature of the northern and southern hemisphere. We were now in the midst of December, which answers to our June, and the latitude observed at noon gave only 51° 5′ south, notwithstanding which we had already passed several pieces of ice, and the thermometer stood at 36°. The want of land in the southern hemisphere seems to account for this circumstance, since the sea, as a transparent fluid, absorbs the beams of the sun, instead of reflecting them.
On the 11th of December, about three o'clock in the afternoon, we passed to leeward of a large piece, or island of ice, at least half a mile in length. The thermometer on deck, which had been at 36° about two o'clock, was risen to 41°, on account of the fair sunshine, which continued all the afternoon: when we came abreast of the ice, the wind directly blowing from thence, it gradually sunk- ↑ Mr. Adanson, on returning from Senegal, brought several bottles filled with sea-water with him, taken up in different latitudes, which being brought to Paris from Brest in the midst of winter, the water in them froze so as to break them; the ice was perfectly fresh, and the residuum of brine was run out. See his Voyage au Senegal, p. 190. Mr. Edward Nairne, F.R.S. has made experiments on sea-water during the hard frost in 1776, inserted in the LXVI. volume of the Philosophical Transactions, which put it beyond a doubt, that solid and fresh ice may be formed from sea-water.
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