286 



CEMENTS, LIMES, AND PLASTERS. 



presented itself in Madison County. He visited the Clarke quarry, 

 examined and tested both the quarry stone and the burned product, 

 and decided that the obstinate lime was really a high-grade natural 

 cement, which required only grinding to make it fit for use. Tests 

 on a larger scale soon proved that his conclusion was correct, and the 

 first American natural cement was put to extensive use in the locks 

 and walls of the middle section of the canal during the years 1818-1819. 



Fortunately, we have a contemporary professional estimate of the 

 value of this material. Wright, in a letter dated in 1820, summarizes 

 the facts regarding White's cement, stating that it "is found to be a 

 superior water cement, and is used very successfully in the stonework 

 of the Erie Canal, and believed to be equal to any of the kind found in 

 any other country. It is pulverized (as it will not slack) and then used 

 by mixing two parts lime and one part sand. It hardens best under 

 water, and it is believed its properties are partially lost if permitted 

 to dry suddenly, or if not used soon after mixing." 



Eighty years of testing devices have hardly given us a more sat- 

 isfactory summary of the properties of natural cements than is con- 

 tained in Wright's last sentence. 



Another contemporary account (1821) states that "the price of this 

 lime, pulverized and burnt and delivered at Utica, is 20 cents the bushel." 



Mr. White took out a patent on this cement and for several years 

 a controversy raged as to the tenability of this patent. This was finally 

 settled, so far as the State of New York was concerned, by the action 

 of the legislature. In 1825 the patent rights for the State of New York 

 were purchased from Mr. White for the sum of $10,000 by the State 

 and immediately thrown open to the free use of the citizens of New 

 York 



It is pleasant to know that the discovery and prompt utilization 

 of this new material by White and Wright were rewarded with equal 

 promptness by their professional advancement on the canal work. 



The chemical character of this first American natural cement is estab- 

 lished by an analysis made in 1822 by Seybert of a sample of the lime- 

 stone used in its preparation. The analysis gave the following results: 



Silica (SiO.) . 11 766 



Alumina (A1 2 O,) 2.733 



Iron oxide (Fe 2 O 3 ) 1 500 



Lime (CaO) 25.000 



Magnesia (MgO) 17 . 833 



Carbon dioxide (CO 2 ) 39. 333 



Moisture 1 . 500 



99.665 



