COMPOSITION AND PROPERTIES OF NATURAL CEMENTS. 275 



TABLE 132. 



COMPRESSIVE STRENGTH OF 4-iNCH NATURAL-CEMENT CUBES. 

 (WATERTOWN ARSENAL.) 



TABLE 133. 

 EFFECT OF HEATING ON COMPRESSIVE STRENGTH. (WATERTOWN ARSENAL.) 



Ratio of compressive to tensile strength. The ratio between the 

 compressive and tensile strength is apparently, in the natural cements, 

 considerably lower than in Portland cement. 





