Lieutenant Gunnison, who has surveyed the great basin of the Salt Lake, states the water to be about one-third salt, which it yields on boiling. Its density is considerably greater than that of the Red Sea. One can hardly get the whole body below the surface: in a sitting position the head and shoulders will remain above the water, such is the strength of the brine; and on coming to the shore the body is covered with an incrustation of salt in fine crystals. During summer the lake throws on shore abundance of salt, while in winter it throws up Glauber salt plentifully. “The reason of this,” says Lieutenant Gunnison, “is left for the scientific to judge, and also what becomes of the enormous amount of fresh water poured into it by three or four large rivers,--Jordan, Bear, and Weber,--as there is no visible effect.”
It has been proved by experiment that the rapidity at the bottom of a stream is every where less than in any other part of it, and is greatest at the surface. Also, that in the middle of the stream the particles at the top move swifter than those at the sides. This slowness of the lowest and side currents is produced by friction; and when the rapidity is sufficiently great, the soil composing the sides and bottom gives way. If the water flows at the rate of three inches per second, it will tear up fine clay; six inches per second, fine sand; twelve inches per second, fine gravel; and three feet per second, stones the size of an egg.--_Sir Charles Lyell._
M. Peligot has ascertained that the Water of the Artesian Well of Grenelle contains not the least trace of air. Subterranean waters ought therefore to be _aerated_ before being used as aliment. Accordingly, at Grenelle, has been constructed a tower, from the top of which the water descends in innumerable threads, so as to present as much surface as possible to the air.
The boring of this Well by the Messrs. Mulot occupied seven years, one month, twenty-six days, to the depth of 1794½ English feet, or 194½ feet below the depth at which M. Elie de Beaumont foretold that water would be found. The sound, or borer, weighed 20,000 lb., and was treble the height of that of the dome of the Hôpital des Invalides at Paris. In May 1837, when the bore had reached 1246 feet 8 inches, the great chisel and 262 feet of rods fell to the bottom; and although these weighed five tons, M. Mulot tapped a screw on the head of the rods, and thus, connecting another length to them, after fifteen months’ labour, drew up the chisel. On another occasion, this chisel having been raised with great force, sank at one stroke 85 feet 3 inches into the chalk!