Page:Twenty Thousand Verne Frith 1876.pdf/237

 against the water—on the 14th January we were beneath all lands. The speed of the Nautilus was slackened, and she became very capricious in her movements, sometimes sailing beneath and sometimes at the surface of the water.

During this portion of the trip Captain Nemo made some very interesting observations respecting the temperature of the sea at different depths. Under ordinary circumstances the results are obtained by means of complicated instruments, and are at least doubtful as regards theometric soundings, as the glasses frequently break under the pressure of the water, or of those appearances based upon the principle of the variation of the resistance of metals to the electric currents. The results thus obtained cannot be really depended upon.

Captain Nemo, on the contrary, went down to ascertain the temperature in those depths, and his thermometer, put in communication with the various zones of liquid, gave him surely and immediately the looked-for temperature. Thus it was, whether in filling the reservoirs, or in descending obliquely by means of the “inclined planes,” the Nautilus attained successively the depths of 3,000, 4,000, 5,000, 7,000, 9,000, and 10,000 yards, and the definite result of these experiences was that the sea gave a permanent temperature of 4½° at a depth of 1,000 yards in all latitudes. I followed his experiments with the greatest interest. Captain Nemo was passionately fond of this work. I often wondered what was the use of all these observations. Was it for the benefit of his fellow-creatures