EXPERIMENT STATION BULLETINS. 



351 



apparently sound tile so as to expose them to the action of the elements, 

 to the action of water in a river bed — to determine what effect a large 

 amoimt of water coming in contact with the surface would have — and 

 to the action of sewage by placing them in the discharge waters at a 

 sewer outlet. 



Tile used in these experiments were left exposed to the conditions 



Fijf. 2. — Apparatus used in determining the effect of various solutions on 



experimental concrete cups. 



described for about four months, at the conclusion of which time none 

 showed any evidence of having been affected by the several conditions of 

 exposure described. Porous tile were placed in soil, and water caused to 

 percolate through their walls. Here again no disintegration was notice- 

 able; but analyses of the water which had passed through the tile struc- 

 ture showed that some of the cement had been dissolved. It should be 

 mentioned here, however, that tile can be manufactured so that under the 

 usual conditions in drains, water will not percolate through the wall 



