158 C. W. DAKLEY. 



is of the class known as mild steel or ingot iron, with a breaking 

 strength of not less than twenty-eight tons per square inch of 

 of original section, and an extension of at least twenty per cent, 

 in ten inches. 



Diameter of tank 100 feet, height 34 feet 2^ inches, constructed 

 of nine tiers of steel plates, each 14 feet 3| inches by 4 feet, except 

 the top tier where the plates are 4 feet 6 inches wide ; the thick- 

 nesses of the plates are as follows, two tiers of 1 inch thick, one 

 each of |", f ", § ", J", § ", and two of -jV on top. Horizontal seams : 

 lap jointed, single riveted. Vertical seams butt jointed, with 

 double cover plates and double riveted, all holes drilled through- 

 out. 6" by \" and 6" by -§" filling strips are riveted to the bottom 

 plates on the outside and inside respectively between the covers 

 to make the bottom rigid and uniform in thickness. 



The bottom plate stands in a groove in a cast iron ring shoe or 

 base plate, cast in lengths of about 7\ If" the bottom of which 

 is 7" wide and planed all over to take a fair bearing on a concrete 

 surface which was accurately rendered over. 



Cast iron stops are embedded in the concrete and stand up about 

 one inch, these are placed at distances of about 3'. 7" apart, their 

 use being to keep the tank from moving off its foundation with 

 expansion and contraction, as it is well known that iron structures 

 such as this have a tendency to expand and contract in one direc- 

 tion. The bottom is formed of concrete 12 inches thick, thickened 

 to about 1'. 9" round the edge under the shell of the tank, and on 

 top of the concrete is laid a coat of rendering and then two courses 

 of brick in cement mortar, the upper course being rendered over. 



Many designs were prepared for ensuring a water-tight con- 

 nection between the iron shell and concrete bottom, but finally 

 the one adopted was decided upon and so far it promises to be 

 very successful ; this is shewn to a large scale on Plate xv., 

 and may be described as follows : — 



The groove in the cast iron base plate previously referred to is 

 made 3 inches deep and 3§" wide; the tank shell which is 2f " thick 



