LAYING TILE DRAINS. 217 



They are generally a little crooked, and when put together will 

 leave places that you can put your finger through. These 

 places should not be left open. In clay soil or sandy soil a 

 crack as large as a quarter of an inch should never be left. If 

 you do leave such an opening you are very likely to have some- 

 thing work in that will obstruct your drain. But the obstruc- 

 tion of drains by filling depends very much upon the slope. It 

 requires a great deal of care to lay a drain where there is but 

 little fall. You may lay a drain well enough with five or six 

 inches fall in a hundred feet, if you will lay your tiles with a 

 continuous slope. If you have water running in your drain 

 when you are laying the tiles you can lay by that. But, ordi- 

 narily, you should engineer more carefully than that. You 

 should draw a chalk line above the drain and keep the slope by 

 measuring downward from that. If you lay two or three by 

 guess you will be surprised to see how much you get out of the 

 way — frequently two or three inches, without perceiving it at 

 all. If you rise but two inches, and sand enters, it will most 

 likely fill up until the drain is completely stopped ; whereas, if 

 you have a continuous fall, ever so little, it will keep itself clear. 



Where I could get spent tan from a tannery, I have generally 

 found that as convenient as anything to cover the joints. Throw 

 a shovelful upon the joint and let the men tread it down. If 

 you cannot get that, get turf, and press it down and secure the 

 joint in that way. The object is to secure it, in the first place. 

 All the water that comes in is merely what soaks in at tlie bot- 

 tom. If you can once get your drain fairly in and the earth 

 packed down and settled, there is no difficulty afterwards about 

 their filling. The great difficulty is, that you put the tiles in 

 carelessly, and the first heavy rain that comes breaks in from 

 the surface, and you meet with your misfortune generally very 

 early in your experiment. 



A Member. Would not sawdust answer as well as tan ? 



Mr. French. I should think it would. There is this advan- 

 tage in using this kind of material, that if it gets into the drain, 

 it will float out. It is very objectionable to pack in a parcel of 

 loose stones about the tiles, because that merely keeps an open- 

 ing above them, which is just what you do not want. There is 

 one thing you may depend upon — you oauuot keep the water 

 out of tiles unless you cement them. You may put on any- 

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