626 CEMENTS, LIMES, AND PLASTERS. 



previously certified in writing by the consumer to be of satisfactory 

 quality. Payment for such tests and analyses to be made by the con- 

 sumer, the manufacturer supplying the cement required for the same 

 free of charge. When consignments of less than 100 tons have to be 

 supplied, the maker shall, if required, give certificates for each delivery, 

 to the effect that such cement complies with the terms of this standard 

 specification, with regard to quality, tests, and chemical analyses, no 

 payment being made by the consumer for such certificate nor for the 

 making of such tests and analyses. 



(5) Should it be deemed more convenient by the consumers that 

 the samples for testing should be taken at the makers' works before 

 delivery, the latter are, in that event, to afford full facilities to the inspector 

 who may be appointed by the consumers to sample the cement as he 

 may desire at the makers' works, and subsequently to identify each 

 parcel as it may be dispatched, with that sampled by him. No parcel 

 is to be sent away unless a written order has been previously received 

 by the makers from the said consumer to the effect that the material 

 in question has been approved. 



Fineness and sieves. (6) The cement shall be ground to comply 

 with the following degrees of fineness, viz.: 



The residue on a sieve 76X76 = 5776 meshes per square inch is not 

 to exceed 5 per cent. 



The residue on a sieve 180X180 = 32,400 meshes per square inch 

 is not to exceed 22J per cent. 



The sieves are to be prepared from standard wire; the size of the 

 wire for the 5776 mesh is to be .0044 inch and for the 32,400 mesh 

 .0018 inch. The wire shall be woven (not twilled), the cloth being 

 carefully mounted on the frames without distortion. 



Specific gravity. (7) The specific gravity of the cement shall be not 

 less than 3.15 when sampled and hermetically sealed at the makers' 

 works, nor less than 3.10 if sampled after delivery to the consumer. 



Chemical composition. (8) The cement is to comply with the follow- 

 ing conditions as to its chemical composition. There shall be no excess 

 of lime, that is to say, the proportion of lime shall be not greater than 

 is necessary to saturate the silica and alumina present. The percent- 

 age of insoluble residue shall not exceed 1.5 per cent; that of mag- 

 nesia shall not exceed 3 per cent, and that of sulphuric anhydride shall 

 not exceed 2.5 per cent. 



Tensile tests. (9) The quantity of water used in gauging shall be 

 appropriate to the quality of the cement, and shall be so proportioned 

 that when the cement is gauged it shall form a smooth, easily worked 



