146 



CEMENTS, LIMES, AND PLASTERS. 



Comparison with sandstone. Lime-sand bricks are frequently com- 

 pared, as to physical properties, with natural sandstones. One example 

 of such a comparison, made by an enthusiastic advocate of lime-sand 

 bricks, is given on page 142 of this volume. In the table below the 

 results of a large number of tests of natural sandstones are summarized. 



TABLE 59. 

 SUMMARY OF TESTS OF NATURAL SANDSTONE. 



Comparing these results with those on lime-sand brick given in 

 table 57 above, it will be seen that the average natural sandstone is far 

 superior in every way to the lime-sand brick. 



Statistics. In its recent revival the lime-sand brick industry in 

 the United States dates back only to 1901, at which date a plant 

 was established at Michigan City, Ind. Since that time numerous 

 plants have been established throughout the country. No accurate 

 statistics, however, are available as regards amount and value of total 

 product. In this connection the latest issue of the "Mineral Resources 

 of the United States" notes that "the sand -lime brick industry, men- 

 tioned in the last report, made considerable progress during 1903. 

 Several plants had their product on the market, and quite a number of 

 new plants were built during the year, but the large majority were 

 engaged in preliminary work and put no product on the market 

 though they will undoubtedly be factors in the production of 1904. 

 Returns covering 16 operating plants show a marketed product of 

 20,860,000 brick, valued at $155,400, an average of $7.45 per thousand. 

 Of these 16 operating plants three were located in Michigan, two each 

 in California, New York, South Dakota, and Texas, and one each in 

 Arizona, Maryland, New Jersey, North Carolina, and Pennsylvania." 



List of references on lime-sand bricks. A number of books and 

 papers dealing with the manufacture and properties of lime-sand bricks 

 are listed below. By far the most important of these, from either a 



