SKETCH OF JAMES B. EADS. 549 



any piers ever built, and through a medium of the most treacherous 

 character. New plans had to be devised to secure success. One pier, 

 weighing forty-five thousand tons, was sunk to a depth of one hundred 

 and thirty-six feet below high-water mark through ninety feet of sand 

 and gravel ; and another one, weighing forty thousand tons, to one 

 hundred and thirty feet through eighty feet of deposit. The loss of 

 life which occurred in the caisson of the east pier resulted from the 

 fact that the situation at such a depth, with the air-pressure it was 

 necessary to endure, was entirely new, and there was no recorded ex- 

 perience by which operations could be guided safely. The erection 

 of the arches developed new problems. The arches had to be de- 

 signed about two and a half inches longer than they are in their 

 present position, because of the contraction which their weight causes 

 throughout the arch. Each half of the arch was built out from the 

 pier and suspended by guys passing through heavy masts erected 

 on each pier, and the central tubes had to be specially fitted for in- 

 sertion. The suggestion was made by his chief assistant to contract 

 the tubes by boxing them up and covering them with iron. This 

 Mr. Eads disapproved of, and devised telescopic tubes for the center 

 of the arch which could be shortened by an internal right and left 

 hand screw-plug, and afterward extended by powerful levers to rotate 

 this plug, steel bands being also provided to cover the plug, flush 

 with the outside of the tube, when the tubes were properly distended. 

 During his absence in London, the chief assistant, confident of his 

 ability to close them with ice, and, having been left with full author- 

 ity, undertook to do so ; but the attempt proved a failure after a 

 trial of eight or ten days, and the telescopic tubes, which ]Mr. Eads 

 had prepared, were then inserted without difficulty. 



In an address delivered at the opening of this bridge, July 4, 1874, 

 Mr. Eads revealed that confidence in his resources and investigations 

 which probably furnishes one of the keys to the secret of his success in 

 this and in his other enterprises. This secret consists in the fact that 

 his courage is always equal to his convictions. Everything, he said, 

 on this occasion, which prudence, judgment, and the present state of 

 science could suggest to him and his assistants had been carefully ob- 

 served in its design and construction ; every computation involving 

 its safety had been made by different individuals, thoroughly com- 

 petent to make them ; they had been carefully revised, time and 

 again, re-examined, verified, until the possibility of error nowhere 

 existed. 



A similar confidence was displayed in his plans for deepening the 

 mouth of the Mississippi by jetties, in which he was opposed by nearly 

 all of the United States engineers, and by a commission of seven of 

 them. The commission in 1874 proposed to avoid the bars by build- 

 ing a canal from Fort St. Philip to Breton Bay. Mr. Eads's plan was 

 to make the river itself deepen a channel through them. Congress 



