CLAYS OF CUMBERLAND COUNTY. 417 



A sample of the so-called gray-burning one (Lab. No. 663), 

 when tested in the laboratory gave the following results : 



Water required for mixing 28.5 per cent. ; air shrinkage, 5.3 

 per cent. Its behavior in burning was as follows: 



Burning tests of clay from Hobartfs east bank, Vineland. 



Cone 05 01 1 



Fire shrinkage, 0.7% 2.3% 2-7% 



Absorption, 16.94% 14-79% 1349% 



Color, pale red light pink reddish 



Condition, nearly steel-hard nearly steel-hard steel-hard 



It will be noticed from this that the clay in the laboratory test 

 burned a brighter color than in practice. The gray color obtained 

 in practice is due largely to the sand used for tempering and mold- 

 ing, as well as in part to' insufficient air in burning. 



Clay-working Industry. 



The clay products made in Cumberland county include common 

 brick, pressed brick and conduits. Soft-mud brick are manufac- 

 tured at Vineland by J. A. Hobart; at Millville, by Golder & 

 Hess; at Bridgeton, by B. Erickson; and by R. T. Green- 

 lee at Belleplain. Stiff-mud brick are made at Buckshutem by 

 A. E. Burcham. Conduits are manufactured at Clayville by the 

 Globe Fireproofing Co. 1 Both buff and red front brick are pro- 

 duced at Rosenhayn by Kilborn & Gibson. The stiff-mud process 

 is used. 



Some of the yards have been in operation for a considerable 

 period of time. 



1 Since writing this (1903), we learn that this factory has been closed and 

 the Clayville clay is now chiefly shipped to Philadelphia for terra cotta. 



27 CI, G 



