112 CEMENT AND CONCRETE 



101. Pre-historic Uses of Concrete. Altho we now 

 find concrete being used in nearly all types of construction 

 work, it is only of recent years that the cement industry has 

 been developed. Some form of cement was used thousands 

 of years ago. The ruins of Babylon and Nineveh show traces 

 of it, as does the Pantheon of Rome. It is said that the pre- 

 historic people of America the Aztecs and Toltecs used a 

 cement mortar that has been so durable that the mortar 

 joints are projecting where the adjacent stones have been 

 worn away by the weathering action during the ages. 



There is little evidence of the use of cement during the in- 

 tervening period from three or four thousand years ago up to 

 the beginning of the nineteenth century. During this period, 

 the art of making cement seems to have been lost and the 

 builders of the Middle Ages had to resort to the use of lime 

 and silt mortars, which were not very durable, as evidenced 

 by the ruins of this age. 



102. Re-discovery of Cement. The re-discovery of the 

 method of manufacture of hydraulic cement, a cement that 

 will set or harden under water, was made by John Smeaton, 

 an English engineer, in 1756. He discovered that limestone 

 containing clay, when burned and then ground until very fine, 

 produced a material which would not only set under water, 

 but also resist the action of water. This we call natural ce- 

 ment. The manufacture of this natural cement on a com- 

 mercial basis is credited to Joseph Parker, who established a 

 factory in 1796 and called his product Roman Cement. Other 

 factories were established in Europe about the same time. 



103. Natural Cement in America. In 1818, Canvass 

 White established a factory at Fayetteville, New York, for 



