TILE DRAINAGE. 77 



which can not be made so tight that they will not admit the very 

 small amount that will need to enter at each space." 



Of the fifteen miles of tile drains on my little farm, nearly half 

 are hard potter-clay tiles, most of them glazed, and about as hard 

 as a jug or earthen crock. They can not and do not crumble or 

 flake with the frost, even at the outlets, where they are constant- 

 ly freezing and thawing while wet : but the brick-clay tiles at 

 the outlets flake and shell to pieces with the frost. The glazed 

 potter-clay tiles drain the land exactly as well as the porous 

 ones, so far as I can see, for both sorts work perfectly. I have 

 sometimes had the whole bottom course of piles of brick-clay 

 tiles, lying directly on the ground, shell all to pieces in a single 

 winter with our frequent rains and quick freezes and thaws. 

 And so I prefer the hard tiles if they can be had at about the 

 same price. As they are stronger, and burned harder, they can 

 be made thinner and lighter than the brick tiles, and hence cost 

 less for freight and handling. I have just weighed some with 

 the following results : 



3-inch, soft, 2 Ibs. 13 oz. ; hard, 2 Ibs. 8 oz. 

 3-inch, soft, 5 Ibs. 13 oz.; hard, 4 Ibs. 2 oz. 

 4-inch, soft, 7 Ibs. 6 oz. ; hard, 6 Ibs. 8 oz. 



There is less difference in weight than in size, as the soft ones 

 are lighter in specific gravity ; and there is less difference in 

 weight than I supposed until T tested them; also less in propor- 

 tion in the two-inch ones. 



Still, I think the brick-clay tiles will endure for centuries, ex- 

 cept at the outlets, if laid below frost, and hard burned. Each 

 one should show clear red color, and give a clear metallic ring 

 when struck with a hammer, or be rejected. 



W. I. CHAMBERLAIN. 



In brief, my advice is, use hard tiles if you can get them at 

 about the same price as the soft or brick-clay ones. If not, 

 then use the latter, but see that they are well burned, and 

 use the potter-clay, or hard tiles, near all outlets, and for a 

 rod or two back from all outlets. And whichever sort you 

 use, do not delude yourself with the belief that the water 

 enters the drains through the pores of the tiles. It enters at 

 the joints. Sheep will not jump a high fence when a gate 

 stands wide open. Also insist on buying with the tiles a suffi- 

 cient number of U T joints" or " Y joints," or, at least, of 

 tiles with holes cut for joints wherever the water enters the 

 main drain from the laterals. 



Fig. 20, page 80, which illustrates many points to be 



