CONSTITUTION, ETC., OF PORTLAND CEMENT. 



575 



(barium and strontium cements) possess strong hydraulic properties, 

 and are volume constant in water for a few days, but owing to the 

 greater solubility in water of barium and strontium hydrate than of 

 lime hydrate, the material after setting is much more readily attacked 

 by water than is lime cement, strontium hydrate being about twice 

 as soluble as calcium hydrate, and barium hydrate about eight times as 

 soluble." 



References on the constitution of Portland cement. The following 

 brief list will serve as an introduction to the mass of literature on this 

 subject: 

 Bonnami, H. Fabrication et contiole des chaux hydrauliques et des ciments. 



8vo, 276 pp. Paris, 1888. 

 Le Chatelier, H. Tests of hydraulic materials. Trans. Amer. Inst. Mining 



Engineers, vol. 22, pp. 3-52. 1894. 

 Newberry, S. B. and W. B. The constitution of hydraulic cements. Journ. 



Soc. Chem Industry, vol. 16, pp. 887-894. 1897 

 Richardson, C. The constitution of Portland cement. Cement, vols. 3, 4, 5. 



1903-1905 

 Richardson, C. The constitution of Portland cement from a physico-chemical 



standpoint. 12mo, 20 pp. Long Island City, N. Y., 1904. 

 Richardson, C. The setting or hydration of Portland cement. Engineering 



News, vol. 53, pp. 84-85. Jan. 26, 1905. 



Composition of Portland cements. The chemical composition of Port- 

 land cements has been changing slowly in one direction since 1850. This 

 is well brought out by the analyses of old Portland cements given in 

 the following table, when compared with the analyses of modern Port- 

 lands given in Table 221. 



TABLE 220. 

 ANALYSES OF PORTLAND CEMENT, 1849-1873. 



Reports Vienna Exposition, 

 Proc. Institution Civil 



1. Manufactured about 1873 by I. C. Johnson & Co., England. 



vol. 4, pt. D, p. 35. 



2. Manufactured about 1849 in England. Analyzed by Pettenkofer. 



Engineers, vol. 62, p. 77. 



3. Manufactured about 1873 in England. Analyzed by Feichtinger. Reports Vienna Exposition, 



vol. 4, pt. D, p. 37. 



4. Manufactured about 1873 in Austria. Analyzed by Wagner. Reports Vienna Exposition, 



vol. 4, pt. D, p. 37. 



