144 



CEMENTS, LIMES, AND PLASTERS. 



them and frozen in the open air, the thermometer ranging from 4 degrees 

 to 20 above zero. This was repeated four times, thawing in warm 

 water each time. They were then frozen in salt and ice (temperature 

 being above freezing-point) three times. The entire process did not 

 have any bad results with the whole brick. The pieces scaled a little 

 at the edges, probably due to small pieces loosened by the breaking of 

 the brick. Another brick was placed in open air in a freezing tem- 

 perature and water allowed to drip and freeze on it until coated with 

 ice without any bad results. 



Two specimens of lime-sand brick (Huennekes system) were tested 

 in 1904 by Prof. Marston, giving compressive strengths respectively 

 of 3210 and 2097 Ibs. per square inch, and absorptions of 10.9 and 

 11.0 per cent. 



In 1904 Prof. Woolson tested several lime-sand brick made on the 

 Schwarz system, with the following results. 



TABLE 55. 

 COMPRESSION TESTS, LIME-SAND BRICK. (WOOLSON.) 



In Table 56 are given the results of a series of tests made at 

 Chariot tenburg on various brands of lime-sand brick made in Germany. 

 It will be seen that these results are very low. 



TABLE 56. 

 PHYSICAL TESTS OF LIME-SAND BRICKS. (CHARLOTTENBURG.) 



Trans. Amer. Ceramic Soc., vol. 4. 



