78 



CEMENTS, LIMES, AND PLASTERS. 



TABLE 21. 

 TENSILE STRENGTH OF KEENE'S CEMENT. 



An American Keene's cement made in Kansas was tested in 1892 by 

 O. S. Carll for tensile strength with the following results. The cement 

 was mixed neat, with enough water to make a stiff plaster. 



TABLE 22. 

 TENSILE STRENGTH OF KEENE'S CEMENT. 



Mack's cement * consists of dehydrated gypsum (flooring-plaster) 

 to which 0.4 per cent of calcined sodium sulphate (Na2S04, Glauber's 

 salts) or potassium sulphate (K 2 S0 4 ) has been added. " This cement 

 is unusually hard and durable, sets quickly and unites minutely with 

 the material on which it is placed. It is used as a covering for wire 

 mesh on walls and ceilings, as well as for floors, and may be mixed with 

 sand or ashes. Its surface is but slightly porous and for this reason 

 absorbs but little oil when covered with paint." 



References on dead-burned and hard-finish plasters. 

 Eckel, E. C. Plasters and hard-finishing cements in the United States. En- 



gineering News, vol. 49, pp. 107, 108. Jan. 29, 1903. 

 Orimsley, G. P. [Hard-finish plasters.] Vol. 5, Reports Kansas Geological 



Survey, pp. 115-118. 1899. 



Redgrave, G. R. Calcareous cements. London, 1895. Pp. 196-199. 

 Rohland, P. [Influence of catalysers on velocity of hydration of plasters, etc.] 



Zeitschrift anorganische Chemie, vol. 31, pp. 437-444. Abstract in 



Journ. Soc. Chem. Industry, vol. 21, p. 1233. 1901. 

 Van't Hoff and Just, G. Der hydraulische oder sogenannte Estrichgips. 



S : tzungsberichte der Kgl. Preuss. Akad. der Wissenschaften, 1903, 



vol. 1, pp. 249-258. 

 Wilder, F. A. The gypsum industry of Germany. Vol. 12, Reports Iowa 



Geological Survey, pp. 192-223. 1902. 



* Wilder, F. A. Gypsum industry of Germany, p. 208, vol. 12, Reports Iowa 

 Geol. Survey. 1902. 



