BRICK AND BUILDING STONE 



277 



tension, due to the lateral flow of mortar, instead of in compression. 

 From a series of thirty-eight tests made at the Watertown Arsenal * 

 on piers of common brick, it was found- that the maximum compres- 

 sive strength varied from 964 lb./in. 2 to 2978 lb./in. 2 . The mortar 

 in this case was composed of one part Eosendale cement and two 

 parts sand. The bricks used in these piers developed only one half 

 their compressive strength. The compressive strength of soft brick 

 may go as low as 500 lb./in. 2 , and that of paving brick as high as 

 15,000 lb/in. 2 , when used in piers. 



The following table gives the results of tests of the compressive 

 strength of common brick made at the Watertown Arsenal. The 

 compressed surfaces were bedded in plaster of Paris, and the bricks 

 were tested whole. 



COMPRESSIVE STRENGTH OF COMMON BRICK 



* Watertown Arsenal Report, 1884. 



