3 t0 THE IMPROVEMENT OF RIVERS. 



either before storage or afterward, will be deducted from any sums due or to become 

 due him. The United States will use all possible means to keep a supply of cement 

 on hand, sufficient to prevent any delay in the progress of the work, but should such 

 delay occur from any rause. no claim for damages caused by such delay shall be ma<K- 

 by the contractor against the United States. The contractor must collect, bale up, 

 and return to the railway station all the sacks, free of expense to the United States. 



(Note. If the contnu t<>r is to supply the cement, the specification may be changed 

 to the following: 



All cement must be supplied by the contractor, and may be of the following 



standard brands The use of more than one brand in the same wall will 



not be permitted above the height of feet above the foundation. The contractor 



must protect the cement from injury while in the cement shed or in handling, as any 

 cement wetted or otherwise damaged will be rejected. He shall permit access to it at 

 all times by the Engineer or his inspectors, and shall afford facilities for taking out 

 samples. Each car-load must be piled separately, so that any rejected lot may be 

 easily recognized. 



The cement shall be supplied in cloth sacks, four sacks being equal to one barrel, 

 and one barrel to weigh 375 Ibs. net. If the weights as determined by test weighing 

 are found to be below this, the deficiency must be made up without expense to the 

 United States. All packages must be plainly marked with the brand, and any not so 

 marked will be rejected. 



The cement must fulfill the following requirements, tests for which will be made by 

 the United States at the lock site, and no cement will be accepted for use which has 

 not fulfilled them. [See specifications for cement, p. 335, et seq.] 



33. Sand. The sand shall be clean and sharp, free from all earth and vegetable 

 matter, screened and washed if required, and satisfactory to the Engineer in every 

 respect; it shall be kept free from dirt, and stored until well drained. The use of wet 

 sand will not be permitted. 



The sand must fulfill the following specifications for coarseness of grain : 

 To pass through a No. 50 sieve, not more than 50 per cent; to pass through a No. 

 100 sieve, not more than 2 per cent. 



34. Broken Stone. The broken stone shall be hard, sound, and entirely clean. 

 It must range in size from pieces ^ of an inch to pieces i^ inches in diameter. 



The contractor must supply samples of the stone he intends to use, and if such 

 samples are accepted all the stone used must be of equal quality. Accepted stone 

 shall be stored on board platforms, if so directed by the Engineer, and be kept clean. 



35. Gravel. Gravel shall be clean, thoroughly washed, and free from shale and 

 other foreign matter; it must range in size from pieces passing a i^-inch screen to 

 pieces retained on a -rV-inch screen, but may contain sand not to exceed 6 per cent of 

 its volume. Accepted gravel shall be stored on board platforms, if so directed by the 

 Engineer, and be kept clean. 



