Physical Tests of the Devonian Shales of New York State 

 to Determine their Value for the Manufacture 

 of Clay Products. 



By Heinrich Ries. 



The extensive developments, in recent years, of the manufacture of clay 

 products having an impervious or vitrified body, as well as strength and 

 toughness, has led the manufacturers of these goods to experiment consider- 

 ably in order to determine what class of clays is best suited for the production 

 of them. The result of these experiments has been the almost universal 

 adoption of shale for this purpose. 



The production of a vitrified body depends on the proper amount of 

 fusible impurities in the clay, and that these fluxes shall be of such nature 

 that the clay can be brought to vitrification without danger of its becoming 

 viscous. It is in shales that these qualifications are usually found. 



An extensive branch of the clay-working industry depending upon 

 shale for its support, has thus sprung up. The product is principally paving 

 brick and sewer-pipe. 



Some idea of the extent to which shale is used may be gained from the 

 following figures of production given in the " Mineral Resources " of the 

 United States Geological Survey, for 1895. The states given are those in 

 which shale is almost exclusively used. 



PRODUCTION OF VITRIFIED PAVING BRICKS IN 1895. 



STATE. THOUSANDS. VALUE. 



Alabama, , \ 2,300 $23,500 



Illinois, 82,526 643,997 



Indiana, 22,313 204,000 



Iowa 31,704 243,928 



Missouri, 6,816 54,640 



New York, 10,896 121,892 



Ohio, 96,555 787,878 



Total, 



. . 253,110 



675 



$2,079,835 



