STOPPING LEAKS. 97 



with cement grout, and ultimately the spring was forced into 

 another outlet, and further movement of the wall stopped. 



In putting in the apron in front of the outer entrance, more 

 springs were met with ; some of the most important were dealt 

 with by placing over them vertical wooden shoots about 12 

 inches square and funnel-shaped at the bottom ; whilst horizontal 

 shoots of the same kind were laid through the concrete to take 

 the water to the pumps. On completion of the work, the shoots 

 were filled up by pouring cement grout into them. To ensure 

 this being thoroughly done, a wrought-iron pipe 2 inches in 

 diameter, and about fifty feet long, reaching from the top of the 

 lock walls to the apron, was inserted in the upright shoots and 

 the grout poured through it. By this means all the springs 

 were forced into one outlet, which was made of a cast-iron pipe 

 fitted with a valve at the top, so that the spring water might 

 have relief when the pressure of the tide was not counteract- 

 ing it. 



Stopping Leaks. The following description of some experi- 

 ments made by Mr. Kinipple, M.I.G.E., with a view to stopping 

 some bad leaks in a dock entrance are of some interest as 

 showing what can be done in this direction. The work in ques- 

 tion was an old graving dock in the west harbour of Greenock, 

 constructed, it is believed, from the designs of James Watt about 

 the year 1785. For some years it was a question, owing to the 

 leaky condition of the entrance, whether reconstruction or 

 abandonment should be adopted, but before deciding, it was 

 determined to try if the case could be dealt with by other 

 means. With this object in view, 3-inch bore-holes, from 1 to 2 

 feet apart, were put down through the masonry behind the heel- 

 posts into the sand for several feet below the foundations. Bore 

 holes were also put down through the inner and outer aprons, 

 close to, and at a few feet from the sill, all of which were sunk 

 well down into the foundations. Stand-pipes were fixed in the 

 various holes, and thick grout of Portland cement was then 

 poured down ; the idea being that it would penetrate through 

 the various fissures and open joints, and vertically join the bore- 

 holes together, and thereby form in fact a water-tight sheeting of 

 Portland cement. The cement was run in only when the dock 

 gates were open, or when the water was at the same level inside 

 and out, in order that there should be no disturbance of the 

 grout by runs of water, until the cement had set. The result of the 



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