July 9.—The hard clay Foundation of.a_ sand island in the Mississippi River, opposite Memphis, Tenn., is being broken up with charges of dynamite so as to permit the current to wash away this obstruction to river navigation. The island, which is of recent formation, is the result of rapid sedimentation at this point, we are told by P. H. Williams, of Chattanooga, ing in The Hercules Mixer" Imington, Del.). About eight years ago, he says, a little gravel bar was noticed in the Memphis harbour. To-day the island covers a good many acres. It has almost caused boats to abandon the harbour, with a consequent injury to Memphis—shipping. The Mississippi River Commission have been using every known.means to keep this harbour open, employing dredging-machines and compressed air, but with only partial success. He goes on:
"In December, 1920, the writer received a demonstration order for one ton of 20 per cent. Farm Dynamite. The idea was. to break the hard clay pan under about 30 feet of sand, so that erosion, assisted by dykes on the other side of the river, would wash the obstruction away. To do this, holes were placed 31 feet in the ground. These went about five feet into the hard clay foundation. It was necessary to use a well drill, loading the holes through an eight-inch pipe. The dynamite was tied in bundles of seven sticks each, and the holes were filled within five feet of the top, requiring from 220 to 250 pounds each. The holes were staggered, first 10 feet from the face of the bank, then 15 with a distance of 121 feet between holes. The results were excellent, for the hard pan was broken to a layer of quicksand and the bottom could not be found. Eighteen holes, loaded with 230 pounds each, blasted a 315-foot section 65 feet wide and broke the ground all xround for 100 feet farther back.
"Tt is believed that by—later loosening this island with dynamite, the river, assisted by dykes on the opposite side, will cause the so-called 'Isle of Mud' to wash away, One of the local newspapers (issued in January, 1921) referred to the work as follows:
A Harris or ENGINEERS.
"Tt was announced by engineers several weeks ago that the point projecting into the river at the first bend off Hopefield was to be dynamited before another high water. It is believed a heavy current will be set in by the removal of a clay bank and will aid in washing away the "Isle of Mud" that has interfered with the Memphis harbour since 1910.
"The work of the engineers has been quietly going on for several days. While there were other
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