246 CLAYS AND CLAY INDUSTRY. 



Tempering. — In the machinery used for tempering, it was 

 noticed that the use of the ring pit predominates, because it is 

 commonly associated with the soft-mud method of manufacture, 

 but at some yards the clay does not go through any tempering 

 proc'ess whatever. The statistics are as follows : 



Number of yards reported, 69 100 % 



Using ring pit, 34 49-2% 



pug mill, 20 29 % 



soak pit, 8 H-5% 



no tempering machinery, 7 10.1% 



At those where no> tempering machinery is employed, the clay 

 is sufficiently moist as mined to be fed into a stiff-mud machine. 

 This is chiefly true of the Clay Marl belt along the Delaware 

 river in Burlington and Camden counties. 



Molding. — Reports of the molding methods in use were ob- 

 tained from the same number of yards, as below : 



Number of yards reporting, 69 1 100 % 



Using soft-mud process — 



steam power, 37 48.7% 



hand power 9 1 1.8% 



horsepower 6 7-8% 



Using stiff-mud process — 



end cut. . 14 18.4% 



side cut, 8 10.5% 



dry press, 2 2.6% 



This indicates the prevalence of the soft-mud method through- 

 out the State. The percentage of these would be still larger if 

 all the yards were included, since there are several others in the 

 northern and northwestern part of the State making soft-mud 

 brick. 



The use of the stiff-mud process is confined chiefly to yards 

 along the Delaware river and the neighboring region, many of 

 which employ the Clay Marls I and II wholly or in part for brick- 

 making. 



Drying. — Here again the method employed is closely related 

 to the molding processes, but the system of drying by tunnels is 



1 Several yards use two or more methods in molding brick. 



