commenced. 



Heal progress in the United States dates from 1832, 

 when the Kyanizing process, using bichloride of mercuty, was 

 developed. In 1837 two other processes were introduced: the 

 Burnett process, using zinc chloride, End the Bethel process, 

 using ctal tar creosote. These last processes are very large." 

 in use today. 



The idea of timber preservation at first made very 

 Slow growth in this country, on account of the large supply 

 of cheap and durable timbers and the grneral disregard shown 

 toward economy in the use of natural resources. In 1385 there 

 were only three pressure plants in the United States; and in 

 1895 tnly l. Since then, however, the industry has grown 

 rapidly; in 1913 there were 117 plants. 



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