HISTORY OF CIVIL ENGINEERING IN NEW SOUTU WALES. 627 



of two feet per mile continues to near the twenty-four and tliree- 

 quarter mile mark, the sides and bottom protected with pitching 

 nine inches in tliickness. 



The Badgelly Tnnnel occurs at a little beyond the twenty and 

 a-quarter mile mark and is three thousand seven hundred and 

 eighty-three and three-quarter feet in length with a piece of covered 

 way four hundred and tlu'ee feet long beyond the outlet. 



The Mallesmain Tunnel at twenty-two and three-quarter miles 

 is seven hundred and three and a-half feet in length also with 

 covered way sixty-three feet and one hundred and forty-two feet 

 in length at the inlet and outlet ends respectively. 



The Box Tunnel at twenty -four and three-quarter miles is on a 

 revei'se curve, and is four hundred and five and one-third feet in 

 length. These tunnels ai'e lined and are similar in grade and 

 cross section to the Sugarloaf and Mount Anna Tunnels. The 

 water emerging from the Box Tunnel is conveyed by a canal with 

 sloping sides giving a breadth of water at the surface of sixteen 

 and three-quarter feet, and a depth of six feet, the gradient being 

 four feet per mile, which continues to about the twenty-five and a 

 quarter mile mark ; after which it enters a semicircular canal, 

 with a surface width of eleven and a-half feet and depth 

 three and a quarter feet on a gradient of twenty-eight 

 and a-half feet per mile, which extends to about the 

 twenty-seven and a-half mile mark. It should be mentioned that 

 there are sluice gates and a waste weir at the termination of the 

 four feet per mile gradient near twenty-five and a-quarter miles. 

 For the next half mile the gradient is reduced to nine feet per 

 mile, with an increased section ; it then passes into an ordinary 

 canal with sloping sides on a grade of two feet per mile. The 

 gradient is curved from the end of the tw^enty-eight and a-half 

 feet per mile gradient to the commencement of the nine feet per 

 mile gradient, and again from the end of this gradient to the 

 commencement of the two feet per mile gradient. The semicircular 

 section of the canal consists on the steep grade of six inch pitchers 

 set in cement and grouted on four inches of concrete ; the nine 

 feet to the mile gradient consists of eight inch pitchers set in 

 cement and grouted, and the whole is topped with a coping of 

 concrete. 



At thirty -four and a-half miles the water enters the Cecil Hills 

 Tunnel, 10,608 feet in length, through two lengths of covered 

 way, eight hundred and forty-five feet and four hundred and 

 forty-five feet long respectively, to the Devil's Back and Calmsley 

 Tunnels, the length of which are nine hundred and sixty-four and 

 two thirds feet and 1,239 feet I'espectively, with a small piece of 

 open canal intervening, then in canal on a gradient of two feet 

 per mile for one and a-quarter miles, through Weston's Tunnel, 

 four hundred and fifty and three-quarter feet in length ; again in 

 canal for a little over three-quarters of a mile and through the 



