MECHANICS AND USEFUL AKTS. 91 



attached, and the pipe lowered to its bed by two separate movements, 

 the first to bring it in a line of suspension conforming to the bottom 

 of the river ; the second, to lay it upon every point of its bed at the 

 same time. From the moment when the first boat started from the 

 island until the work was finished there elapsed 17 minutes. During 

 this time, besides the other necessary work, about one hundred anchors 

 were attached to the pipe. Apparently the work was thoroughly per- 

 formed, and had it not been for an untoward accident it would have 

 been. A large vessel, disregarding the signals and sentinels which 

 had been placed to prevent all craft from taking this channel, bore 

 directly across the line at the moment when the men were engaged in 

 attaching the anchors greatly endangering the lives of those in. its 

 course. The result was some confusion, and the consequent failure of 

 one of the men to put on all the anchors at his station. This was not 

 known at the time the tide was now making rapidly, and the order 

 was given to lower. This was at the end of December, 1850. The 

 pipe performed its work very well until the beginning of June follow- 

 ing, when, failing to supply the island with water, it was taken up to 

 ascertain the cause of failure. It was found that at the point above 

 mentioned several anchors had been omitted, leaving nearly fifty feet 

 of the pipe subject to the vibratory action of the tide. The constant 

 abrasion against the sharp rocks at the bottom, consequent upon this, 

 had of course chafed the pipe through at one or two points in the space 

 thus unprotected. Except in these points it was comparatively unin- 

 jured by abrasion. The rest of the pipe was now subjected to tests, 

 and found to have undergone no perceptible chemical change whatever. 

 Being again proved by the hydraulic press, it stood as much pressure 

 as it did before it was put down. Being convinced, by the winter's 

 experience, of the durability of the material and the advantages it pre- 

 sented in a location like this, and being satisfied that by another method 

 of putting it down all chance of the recurrence of such an accident 

 as the one above described could be obviated, it was determined to use 

 this same kind of pipe again. The second line of pipe was furnished 

 about the 20th of September, and put in its place on the 26th of the 

 same month. To avoid accidents like the one which had rendered 

 imperfect the work of last December, the mode of operation now 

 adopted was different. The pipe being all put together in a continu- 

 ous length, as before, was attached to a line of large boats, which was 

 stretched down the stream, and along the shore of BlackwelTs Island, 

 in the eddy, but in water of sufficient depth to make the proper ar- 

 rangement's for subsequent operations. These boats were stationed at 

 such intervals that the slack of the pipe between them, properly gradu- 

 ated, would conform to the inequalities of the bottom in the line of the 

 destined position of the pipe, the boats themselves being kept in place 

 by being made fast to a hawser 1150 feet long, drawn taught between 

 heavy anchors at the ends of it. The anchors at the upper end were 

 at the point at which the pipe was intended to connect with the 

 Island. The anchors to hold the pipe down were now put on 

 thoroughly, the workmen not being subject to the strength of the tide 

 or danger from sailing craft. As a further precaution against abrasion, 



