Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

ON THE DELUGE. 675 related by Scoresby ;* with what has been found by those who have sounded to great depths ; and with my own practical ex- perience in sounding — has induced me to think that man never will reach the lowest depths of the deepest oceans by any method his ingenuity may contrive; — because the water increases in density with the depth, in a ratio perhaps more than arithme- tical. Every seaman knows that in sounding at great depths very heavy leads must be used with ordinary lines, or very thin lines with ordinary leads ; the object being the same — that of overcoming the augmenting buoyancy of the line by a weight unusually heavy. But line, such as is used for sounding, is not buoyant at the surface of the sea ; a coil of it thrown over- board sinks directly. Then what is it that causes any weight attached to a sounding-line to sink slower and more slowly, and, consequently, in a very dense state. Let us now inquire howincreasing density (from compression alone) might affect an apparatus sent down by a weight, in order to reach the bottom, presuming that the solids composing the float and sinker were incompressible, and retained their form and magnitude during the operation. " Let bees'- wax be a float, and cast-iron a sinker, and let each, for illus- tration, be one cubic foot in dimensions. Let it be possible that at some depth water may be compressed into one-fourth of its bulk at the surface, and still retain the properties of a fluid ; let it also be granted that a solid will swim if specifically lighter than the contiguous fluid, and sink if heavier than an equal volume of the fluid. The specific gravity of bees'-wax is stated to be 964 ; that of cast iron, 7248 ; and that of sea- water at the surface, 1028 : hence the buoyancy of wax immersed in sea- water at the surface, may be called 64, and the tendency of cast-iron to sink, from the same surface, 6220. I>educting 64, we have 6156 as the whole tendency of the mass (wax attached to iron) to sink from the sur- face. Let us now suppose that the machine has attained a depth where the water is compressed into a four-fold density, represented by 41 12 for a cubic foot ; and we have 3148 for the tendency of the wax to float, but only 3136 for the tendency of the iron to sink : and the inclination to ascend rather than descend, might be represented by 12. Thus we see that an apparatus may not be certain of arriving at the bottom of an ocean : as in an opposite manner, a balloon may not reach the highest regions of the atmosphere. Either machine could only attain a position where there would be no tendency either to descend or ascend. Plymouth, 24th Feb. 1837. " William \A'ai.kkr." • Scoreshy's Arctic Regions. 2x2