WALLS ON TRIUNE CYLINDER FOUNDATIONS. 131 



positions required. The concrete is then put in and well rammed 

 so as to secure homogeneity and a smooth surface ; about twelve 

 hours after filling the moulds the division plates are withdrawn, 

 and two days after the wooden moulds are removed. In periods 

 varying from nine days to three weeks, depending upon the 



Above Jtottom of Trench before sinking 



SECTION OF WALL ON LINE A.B. 

 FIG. 100. 



time of year and the weather, the rings are ready for removal 

 and building into the work. The contents of one section or 

 ring complete is 105 cubic yards, the heaviest portion weighs 

 about 6 tons, whilst the total is about 18 tons. 



