476 CLAYS AND CLAY INDUSTRY. 



Physical characters of Drummond's clay. Asbury Park. 





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III 



IV 





Lab. No. 658. 



Lab. No. 696. 



Lab. No. 697. 



Lab. No. 696-} 



Water required, . 



20.9% 



37-3% 



27.0% 



31-2% 



Air shrinkage, . . 



3-3% 



5.6% 



6-3% 



6-3% 



Average tensile 











strength, lbs. 











per sq. in., .... 



107 



182 



137 



258 



Cone 05 — 











Fire shrinkage, 





3-3% 



0.4% 



0.3% 



Absorption, . . . 





28.31% 



20.12% 



23-53% 



Condition, .... 





not steel-hard 



not steel-hard 



not steel-harf 



Color, 





light red 



pink red 



light red 



Cone I— 











Fire shrinkage, 





7.0% 



1.0% 



2.2% 



Absorption, . . . 





16.79% 



16.22% 



17-59% 



Color, 





deep red 

 nearly steel- 



red 



red 



Condition, 





nearly steel- 



nearly steel- 







hard 



hard 



hard 



Cone 3 — 











Fire shrinkage, 



0% 











. 16.87% 









Color, 



. light buff 









Cone ic — 











Fire shrinkage, 



2% 





3.o% 1 



2. 4 % 1 



Color, 



. light gray 









Condition, 



. steel-hard 





steel-hard 1 





I. Yellow, sandy laminated clay, sometimes used in bricks. 

 II. Black, gritty clay. 



III. Very gritty top loam. 



IV. Mixture of II and III. 



From an inspection of the above tests, it will be seen that the 

 yellow, sandy, laminated clay (No. I) burns to a very light color,, 

 has an exceedingly low fire shrinkage, even at a comparatively 

 high cone is quite porous and does not burn hard at a low cone. 



The mixture (No. IV) of the top and bottom layers (No, II 

 and III) produces a material whose water absorption is inter- 

 mediate between the two, and whose fire shrinkage is practically 

 no greater than that of the surface loam. Another effect of the 

 mixing has been to> increase greatly the tensile strength which is 

 rather an interesting point (see page 89). The fire shrinkage 



1 Burned at cone 9. 



