TILE DRAINAGE. 75 



per. I can not state the matter more clearly than 1 did 

 there. 



EXPERIMENTS WITH TILES. 



\\JIKRE DOES WATER GET INTO DRAINS ? ABSORPTION BY SOFT 

 TILES DISPROVED ; VALUE OF HARD TILES. 



Editors Country Gentleman: Some six or eight years ago 

 Prof. N. W. Lord and I made some careful experiments with 

 tiles at the Ohio State University, which seemed to prove beyond 

 question that the water enters tile drains at the joints, and not 

 through the pores of the tiles. I think that I gave some account 

 of the experiments at the time in these columns. Since then I 

 have been in the habit of advising the use of hard tiles made of 

 potters' clay, if to be had at the same price, rather than of the 

 soft red tiles made of brick clay, on the ground of greater 

 probable durability, especially near the outlets. 



Mr. C. G. Elliott, of Rittman, ()., a manufacturer of soft tiles, 

 lately criticised this advice, given by myself, in a western agri- 

 cultural paper, and said that soft tiles are better because porous, 

 admitting the soil water through their pores into the interior of 

 the drains, as the hard tiles confessedly will not. I therefore 

 gave in reply, briefly, my former experiments and certain new 

 ones made with his own tiles sent me by him as fair samples. 

 They were excellent soft or brick-clay tiles. As I have formerly 

 written to some extent in these columns on drainage, I will now 

 report my recent experiments and conclusions. 



First, I took a four-inch tile, medium burned, and set it on 

 end in a deep pail in plaster-of- Paris mortar, and let the plaster 

 harden, inside and outside of the tile. This completely closed 

 the bottom of the tile. I then filled the tile full of water. The 

 water sank perceptibly in the tile with a sort of hissing sound, 

 and the small air-bubbles came to the surface as the pores of the 

 tile greedily drank in the water. In eighty minutes it had sunk 

 two inches, but no water had gone through. I filled it again and 

 left it nine hours. It had then sunk half an inch, but no water 

 had gone through. I filled it again and it sank no more. Appar- 

 ently the same capillary attraction that drank the water into the 

 pores kept it in them, preventing its escape.* 



I reversed the experiment with the same tile, still soaked 

 emptying the water out of the tile and filling the pail all around 

 the empty tile. No 'water came tlirough, and none was absorbed, 

 as the tile was saturated already. I then remembered that water- 

 is said to filter through the brick partition of a cistern. The 

 thought suggested itself, that perhaps the water first got through 

 the cracks between the bricks and the mortar, and then with 



* The reason of tins is explained in Chapter II. of this little book. 

 W. I. C. 



