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Soundings

When it is necessary to know the depth of the water at any point in the river, the test or sounding is made by dropping a 33 foot rope, to the end of which isSoundings fastened a pipe filled with lead.  The pipe is about one and a half inches in diameter and twelve inches in length.  A few inches of heavy chain are put into the pipe, and around this melted lead is poured.  The weight of a lead is between six and ten pounds.  The rope is fastened to a link of the chain that is allowed to extend past the length of the pipe.  The length of the lead line is marked at four feet by a piece of white flannel woven into the rope, at six feet, by a piece of leather, at nine feet by a piece of red cloth; at Mark Twain there is a piece of leather split into two thongs and at Mark Four there is a single leather strip with a round hole.  These signals are recognized by the leadsman as the rope slips through his hands in the darkness.

The sounds are called out as the line drops.  A depth less than Quarter Less Twain is given in feet.  After Mark Four is reached the measurement is usually give as No Bottom.