254 CLAYS AND CLAY INDUSTRY. 



The samples tested were first thoroughly dried, then weighed, 

 and soaked in water for 48 hours, after which they were weighed 

 again. The increase in weight gave the amount of water 

 absorbed, and this, divided by the original weight, gave the per- 

 centage of water absorbed. The percentage of absorption is, 

 therefore, based upon the weight of the dried brick. 



The absorption on 8 different kinds of soft-mud bricks was de- 

 termined. The lowest of these was 5.36 per cent, and the highest 

 18.64 P er cent., but 6 ranged between 12.09 per cent and 14.87 

 per cent. The average of the 8 was 13.39 P cr cen t-, or, omitting 

 the two extremes, it was 13.86 per cent. Curiously enough, the 

 highest and lowest figures belong to bricks from the same yard, 

 but represent two* different banks of clay. The one with the high 

 absorption was red, but lacked in hardness ; the other was hard, 

 but its color was yellowish white with iron specks, and on account 

 of its poorer color it did not command so good a market. The 

 effect of re-pressing is seen in the lower absorption of brick from 

 Trenton in the series given below. 



Absorption tests on 14 kinds of stiff-mud brick from 14 locali- 

 ties ranged from 1.34 per cent, to 14.29 per cent., with an average 

 of 10.19 per cent., which is somewhat lower than the absorption 

 of the soft-mud samples. The following are the figures obtained : 



Table showing absorption of New Jersey brick. 



soft-mud bricks. Absorption, 



Locality. percentage. 



Herbertsville, 5.36 



Trenton (re-pressed), 9-75 



Trenton (not re-pressed) , 12.09 



Farmingdale, 12.97 



Little Ferry. 13-79 



Cliffwood, ■ 14-52 



Herbertsville; 1487 



Sayreville, I4-9 1 



Herbertsville, 18.64 



STIFF-MUD BRICKS. 



Whippany, '. 1-34 



South River, 5-63 



Cliffwood, 7-52 



Rosenhayn, 8.6i 



