Page:Popular Science Monthly Volume 80.djvu/248

244 knowledge, I wrote to Captain Eads calling his attention to my investigations of the Passes and of the origin of mudlumps, and suggesting that, so sure as the main current of the river was turned into the South Pass, mudlumps would necessarily arise; not at once, but within a period of probably twenty to thirty years. Captain Eads replied that, while he appreciated the force of my objection, even a surcease of twenty to thirty years would be of great service to American commerce, and that it would be unfortunate to bring the matter to public notice at that time. To this suggestion I agreed; and so soon as the bill passed Congress, the work was begun with his wonted energy by the distinguished engineer. He, unfortunately, died before its completion, but it was carried out according to his plans by his successors.

For about twenty-five years after the completion of the jetties there was little difficulty in keeping up the required channel depth of 26 feet, 200 feet wide in the South Pass and over the bar beyond the jetties. Within the last six or seven years, however, obstructions began to appear in the channel, which the dredges found great difficulty in removing and which, when removed, seemed to be promptly renewed at the original point. Within the last year it was definitely stated in the newspapers that the obstruction was a "mud bubble upheaved by the gas from the bottom of the river; the mud being so stiff that the dredges could not handle it, and a navigable channel had to be carried around it." I, thereupon, communicated with the engineers in charge of the South Pass navigation and promptly received, from Assistant Engineer C. Donovan, a blueprint of a map showing the soundings in the jetties, and beyond and across the bar; which, by this time, has become a pretty definite ridge, as in the case of the other Passes. This map shows that the current impinges directly against a mudlump mass which has arisen across its course, but has not yet reached the water surface; and a scrutiny of the soundings shows that a maximum depth exists, even now, right at the upstream slope of the newly risen lump. The highest portions of the mudlump are still about twenty feet below the water's surface; whether naturally, or kept so by dredging, I have not learned. No eruption of liquid mud has thus far been reported, although at such a depth it might easily have escaped observation.

This unfortunate verification of my prediction of the event would seem to confirm pretty definitely my theory of the origin of mudlumps in general. As this confirmation is of considerable interest for the