SPECIFICATIONS FOR NATURAL CEMENTS. 279 



Soundness. Tests for checking and cracking and for color will be 

 made by molding, on plates of glass, cakes of neat cement about 3 inches 

 in diameter, inch thick in the center, and with very thin edges. One 

 of these cakes when set perfectly hard shall be put in water and examined 

 for distortion or cracks, and one shall be kept in air and examined 

 for color, distortion, and cracks. 



Engineer Corps, IT. S. Army, 1901 



(1) The cement shall be a freshly packed natural or Rosendale, 

 dry, and free from lumps. By natural cement is meant one made by 

 calcining natural rock at a heat below incipient fusion and grinding 

 the product to powder. 



(2) The cement shall be put up in strong, sound barrels, well lined 

 with paper so as to be reasonably protected against moisture, or in 

 stout cloth or canvas sacks. Each package shall be plainly labeled 

 with the name of the brand and of the manufacturer. Any package 

 broken or containing damaged cement may be rejected, or accepted 

 as a fractional package, at the option of the United States agent in 

 local charge. 



(3) Bidders will state the brand of the cement which they propose 

 to furnish. The right is reserved to reject a tender for any brand which 

 has not given satisfaction in use under climatic or other conditions of 

 exposure of at least equal severity to those of the work proposed. 



(4) Tenders will be received only from manufacturers or their 

 authorized agents. 



(The following paragraph will be substituted for paragraphs 3 and 4 

 above when cement is to be furnished and placed by the contractor: 



No cement will be allowed to be used except established brands 

 of high-grade natural cement which have been in successful use under 

 similar climatic conditions to those of the proposed work.) 



(5) The average net weight per barrel shall not be less than 300 Ibs. 

 (west of the Allegheny Mountains this may be 265 Ibs.) . . . sacks 

 of cement shall have the same weight as 1 barrel. If the average net 

 weight, as determined by test weighings, is found to be below 300 Ibs. 

 (265 Ibs.) per barrel, the cement may be rejected, or, at the option 

 of the engineer officer in charge, the contractor may be required to 

 supply free of cost to the United States an additional amount of cement 

 equal to the shortage. 



(6) Tests may be made of the fineness, time of setting, and tensile 

 strength of the cement. 



