IV ATE R IN FOUNDATIONS. $7 



the waggon road which had passed over this spot. The bottom 

 consisted of a quicksand which could be penetrated with a 

 bar to the depth of 8 feet. This excavation was filled with 

 concrete to a height of 1 1 feet above the bottom. A boil started 

 shortly after the concreting was began, and filled the foundation 

 with water, which continued to rise through a thickness of 11 

 feet of concrete. The hand-pumps had been quite inadequate 

 to remove the water which flowed into this foundation, and 

 much of the concrete was impaired, the water having washed 

 the lime out of it. The removal of the concrete was not 

 attempted until two small chain-pumps had been fixed, each 

 capable of lifting 800 gallons of water per minute. After one 

 of these pumps had been started in the foundation, the imperfect 

 concrete was removed for a depth of 5 feet, and the flow of 

 water which had become very strong was confined to two 

 places by concrete made of Medina cement. This was lowered 

 into the foundation in a box containing one cubic yard ; an old 

 millstone, with a hole in the centre, was set over one of these 

 vents in a good bed of Medina cement, and though some diffi- 

 culty was experienced in forcing the water up the hole, this 

 was eventually done. A hole was made in a second stone, 

 which was in like manner set over the second vent. The holes 

 were afterwards plugged up, but not before great trouble had 

 been experienced with this length of foundation, as the water 

 found its way up in many places through the ordinary lime 

 concrete. After the wooden plugs were driven into the holes 

 in the stones, so great was the pressure of the water below 

 that it oozed up through many spots in the neighbourhood. 

 Much trouble was experienced on the east side of this founda- 

 tion, when two large and several smaller boils had to be confined 

 to holes in stones surrounded by brickwork set in Portland 

 cement. 



Of the six compartments into which the east end of the 

 lock had been divided, one only now remained, of which the 

 greater part lay beneath the east sill. No attempt was made 

 to reach the lower bed of clay 20 feet below the sill level. It 

 was decided that a bed of 6 feet below the bottom of the 

 masonry sill would be sufficient. As the masonry would be 

 9 feet thick, this gave a depth of 15 feet below the sill level 

 for the bottom foundation. The compartment had already been 

 divided into two nearly equal spaces by a row of piles 16 feefc 



