LIV. C. W. DARLEY. 



sufficiently solid to make a safe foundation, thus opening the 

 way for contractors to set up claims which are difficult to dispute 

 or adjust. Also, by employing a staff who are moved from one 

 work to another and thus trained to the class of work, a more 

 uniform standard of construction is obtained, and equally as cheap 

 as if done by contract. 



English, German and Colonial cements have been in use, but 

 an effort is always made to have each dam carried out in one brand. 

 Of late, the Rock brand cement, manufactured near Sydney by 

 Messrs. Goodlet and Smith, has been almost exclusively used. 

 It is packed in bags and is thus cheaply handled or carted. 

 It is delivered as required from the store at Granville into railway 

 trucks, and thus the expense of erecting large storage sheds on the 

 site of the works is saved. The bags are found very useful for 

 covering green concrete and other purposes. 



All the sand used for making up the concrete is washed, the 

 usual apparatus employed being the ordinary "Long Tom" of the 

 gold-digger. A horizontal screen is placed at the head of the 

 trough, this not only removes coarse stuff and vegetable matter, 

 but also assists greatly in distributing the water through the mass, 

 thus freeing the particles from dirt. The dust from the stone- 

 crusher, if granite is being broken, mixed with the washed sand 

 is found to add to the strength of the concrete. 



Stone is broken up into ballast and shivers by the ordinary 

 types of stone-crushers and passed through a revolving screen to 

 separate the various sizes. The "Little Giant" type of crusher 

 has been generally used, as the pin-plates provided with this 

 machine best stand the wear of breaking to the small gauge of 

 1J inch. The pins are of f inch tool steel set in a cast-iron 

 backing. Manganese steel plates have been tried, but sufficient 

 experience has not yet been gained to enable me to express an 

 opinion as to their wearing qualities. 



As a rule, the rock foundations when laid bare are sufficiently 

 rough to give a grip to the concrete, and it is not necessary to cut 



