MECHANICS AND USEFUL AliTS. 43 



SOUTIIPORT PIER. 



This pier, capable of resisting severe strains from wind and 

 water, as experience has prov^ed, capable of sustaining a load of 

 35 tons for each bay, — 3, GOO feet long and 15 wide, with ap- 

 proaches, tool-house, etc, — was constructed for $40,595. The 

 entire number of piles, 237, were sunk in the space of 6 weeks, 

 in a location where work could be prosecuted only at low tide. 



The methods for sinking the iron piles were as follows : The 

 lower ends of the piles were provided with circular disks, 1^ feet 

 in diameter, on which projections or cutters were cast, and 

 through which, at the centre, passed a pipe delivering water from 

 the regular mains under a pressure of 50 pounds to the sq«are 

 inch. The pile was supported and lowered, as necessary, by a 

 small piling machine, and a rotary reciprocating motion being 

 given, the sand, etc., was loosened from beneath and carried away 

 by the stream of water. The water being stopped, the pile set- 

 tled, so as to sustain 12 tons, without moving, in 5 minutes. 



NEW BRIDGES. 



Bridge at Niagara Falls. — They are building a new suspension 

 bridge at Niagara close to the Falls, for carriages and foot pas- 

 sengers. On the American side the towers are within a few hun- 

 dred feet of the Falls, and the cables are already swung across 

 to corresponding towers close to the Clifton House. In some re- 

 spects this bridge is more remarkable than the other. In length 

 it exceeds it 450 feet, being 1,250 feet in the span. The tow^ers 

 are 105 feet high, and are built 13^ feet apart. Unlike the heavy 

 stone columns of the lower bridge, the}' are light wooded trestles, 

 28 feet sc^uare at the base and tapering to the top. When finished 

 they will be roofed and w'eather-boarded. 



The bridge will be sustained by 2 cables, which wore swung 

 last winter when the ice filled the river below the Falls. The 

 lower bridge is sustained by 4 cables. Those of the new bridge 

 are composed of 7 strands of twisted steel wire, each measuring 

 2§ inches in diameter, w4nch form a cable about 9 inches thick. 

 The ends are fastened by the new shackles invented by Mr. 

 Hewlett, of Niagara, in a manner very different from that 

 formerly adopted. The strands of the cable are untwisted at the 

 ends, and hang separately from the tops of the towers. Each is 

 secured to a separate shackle, which looks something like a pulley 

 with a fixed wheel. These are grooved so as to hold tlie cable by 

 means of friction, independent of the fastening at the ends, if 

 necessary. The shackles are of various lengths, so as to divide 

 the strain as much as possiljle, and are secured to a base firmly 

 planted in beds of masonry 18 feet square. This will probably 

 hold the weight of the bridge against an}' ordinary pressure ; and 

 unless the slight towers are racked and weakened by the lateral 

 motion caused by the high winds of the winter season, it will 



