CEMENTS, LIMES, AND PLASTERS. 



INTRODUCTION. 



FEW economic movements, during the past decade, have equaled 

 in importance or interest the marvelous growth of the industries based 

 on the non-metallic structural materials. In this group are included 

 the stone used for building purposes, such clay products as are used 

 in engineering, and, last in order but not in importance, the cementing 

 materials. The production of structural materials in the United States 

 for the years 1902-1903 has been summarized in the following table, 

 for convenience of reference. 



TABLE 1. 

 PRODUCTION OP STRUCTURAL MATERIALS, 1902-1903. 



Of the three subgroups of materials quoted in the above table, the 

 third cementing materials is the subject of the present volume. It 

 will therefore be of advantage to consider the financial statistics of 

 this subgroup in somewhat more detail. The following table (Table 2) 

 gives the value of the production in the United States, for the years 

 1900-1903 inclusive, of the six classes into which the cementing materials 

 may conveniently be divided. On later pages, where these classes are 

 separately discussed, much more detailed statistics are given in regard 

 to each product. 



